1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 12458:1999 The Euro
2、pean Standard EN 12458:1999 has the status of a British Standard ICS 71.100.40 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Surface active agents Determination of stability in hard waterThis British Standard, having been prepared under the direction of the Sector Committee
3、for Materials and Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 June 1999 BSI 06-1999 ISBN 0 580 32269 6 BS EN 12458:1999 Amendments issued since publication Amd. No. Date Comments National foreword This British Standard is the English language v
4、ersion of EN 12458:1999. The UK participation in its preparation was entrusted to Technical Committee CII/34, Methods of test for surface active agents, which has the responsibility to: aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpret
5、ation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which i
6、mplement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not p
7、urport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside fron
8、t cover, the EN title page, pages 2 to 5, and a back cover.CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1999 CEN All rights of exploitation in any form and by any means reserve
9、d worldwide for CEN national Members. Ref. No. EN 12458:1999 E EUROPEAN STANDARD EN 12458 NORME EUROPE ENNE EUROPA ISCHE NORM February 1999 ICS 71.100.40 Descriptors: surfactants, tests, measurements, stability, water hardness English version Surface active agents Determination of stability in hard
10、water Agents de surface De termination de la stabilite a leau dure Grenzfla chenaktive Stoffe Bestimmung der Besta ndigkeit gegenu ber hartem Wasser This European Standard was approved by CEN on 25 January 1999. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulat
11、e 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 standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exist
12、s 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 notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodi
13、es of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Page 2 EN 12458:1999 BSI 06-1999 Foreword This European Standard has been prepared by Technical Committ
14、ee CEN/TC 276 “Surface active agents”, the Secretariat of which is held by AFNOR. 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 August 1999, and conflicting national standards shall be withdrawn
15、 at the latest by August 1999. Annex A is informative. Endorsement notice. The text of the International Standard ISO 1063:1974 was approved by CEN/TC 276 as a European Standard with the following modifications as given below: a) change of units “meq” to “mmol/l”; b) inclusion of an informative anne
16、x A; c) text editorially revised. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Lu
17、xembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.Page 3 EN 12458:1999 BSI 06-1999 Introduction A knowledge of the stability of surface active agents in hard water is of great importance for all the applications of these substances, since the precipitates obt
18、ained with hard water can reduce their effectiveness in practice. The tests specified in this document are carried out with an aqueous solution of calcium chloride of known hardness. In certain cases, it can be necessary to use other ions that give rise to hardness in water (see test report). 1 Scop
19、e This European Standard specifies a method of assessing the stability in hard water of surface active agents which are readily soluble at ambient temperature or slightly higher temperatures. This method is applicable to surface active agents soluble in water at 208C. It can be extended to those whi
20、ch are soluble at approximately 508C. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated referenc
21、es, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 12829, Surface active agents Preparation of water with kn
22、own calcium hardness. (ISO 2174:1990 modified) EN ISO 3696, Water for analytical laboratory use Specification and test methods. (ISO 3696:1987) ISO 835-2, Laboratory glassware Graduated pipettes Part 2: Pipettes for which no waiting time is specified. 3 Terms and definitions For the purposes of this
23、 standard, the following definitions apply. 3.1 hardness of water the hardness of water is due to the presence of soluble alkaline earth compounds and especially of calcium salts; it is expressed in millimoles of calcium (ll) ions per litre 3.2 stability of a surface active agent in hard water the s
24、tability of a surface active agent in hard water is determined by the solubility of the compounds formed by ion exchange between the surface active agent and the calcium ions, or by modification or the colloidal state by ionic forces, salt effect, pH value, etc. 4 Principle Mixing of a solution of t
25、he surface active agent in differing concentrations with hard water solutions of differing known calcium hardness. After leaving the solutions to stand in specified conditions, observation of their appearance, i.e. clearness, opalescence, cloudiness or precipitation. 5 Reagents All reagents shall be
26、 of recognized analytical quality and the water used shall comply to grade 3 in accordance with EN ISO 3696. 5.1 Hard water solutions, prepared according to EN 12829. Solution S 1 , of calcium hardness 3 mmol (= 120,24 mg) of calcium (ll) ions per litre; Solution S 2 , of calcium hardness 4,5 mmol (
27、= 180,36 mg) of calcium (ll) ions per litre; Solution S 3 , of calcium hardness 6 mmol (= 240,48 mg) of calcium (ll) ions per litre. 6 Apparatus Ordinary laboratory apparatus and glassware, together with the following. 6.1 Fifteen test tubes, for example 30 mm in diameter and 200 mm long, graduated
28、at 50 ml. Experience has shown that flat-bottomed test tubes are preferable, as they make it easier to observe cloudiness or precipitates. 6.2 Pipette, 5 ml, graduated at every 0,05 ml, complying with ISO 835-2. 6.3 Thermostatically controlled water bath, for measurements carried out above 208C. 7 P
29、rocedure 7.1 Preparation of test solution Prepare a stock solution of 50 g of the surface active agent in 1 000 ml of water at 208C. If the products are not readily soluble at 208C, prepare the solution at 508C. This temperature shall be stated in the test report. 7.2 Determination Using the pipette
30、 (6.2), transfer 5,0 ml of the test solution (7.1) to one of the test tubes (6.1) and add the hard water solution S 1 ,( 5.1) to give a volume of 50 ml. NOTE Formation of foam can be troublesome and should be avoided when mixing the test solution with the hard water solution. To achieve this, close
31、the test tube containing the mixture with the hand or a bung, turn it slowly upside down and bring it back slowly to the original position. This operation shall take 1 s; repeat it ten times.Page 4 EN 12458:1999 BSI 06-1999 Leave the test tube to stand for more than 1 h but less than 2 h at (20 2)8C
32、 and examine at this temperature for precipitates, cloudiness or opalescence. In the case of a solution which changes with time (soap solution for example), the age of solution to the nearest 5 min, shall be stated in the test report. If it appears that the solubility of the calcium salts increases
33、with temperature, carry out the test at (50 3)8C and make the observation at this temperature. Carry out the determination similarly with 2,5 ml, 1,2 ml, 0,6 ml and 0,3 ml of the test solution (7.1). Proceed similarly with identical volumes of the test solution (7.1) and with the hard water solution
34、s S 2 and S 3 (5.1). 7.3 Scoring Allot to the result of each determination a score number in accordance with the numbering system in Table 1. Table 1 Score number corresponding to the appearance of the liquid Appearance of the liquid Score number (unit value) Clear 5 Opalescent 4 Cloudy 3 Slight pre
35、cipitate 2 Heavy precipitate 1 In case of doubt between the score numbers (for example, cloudiness and slight precipitate), choose the less favourable score number. A liquid which is not clear, but through which objects can be seen, is regarded as opalescent. A liquid which is not clear, and through
36、 which objects cannot be seen, is regarded as cloudy. NOTE Although solutions in hard water of certain commercial surface active agents containing insoluble inorganic products are perfectly transparent, small quantities of crystals can appear at the bottom of the test tube or on the surface of the l
37、iquid. These crystals are entirely different from the colloidal precipitates arising from hardness of the water and it should be necessary to centrifuge the solution, before testing, until it is clear. 8 Expression of results 8.1 Mean stability In general, a surface active agent is given a single st
38、ability figure which represents the “mean stability”. Add the 15 unit values obtained as described in 7.3 to obtain the total value, and calculate the mean stability, as shown in Table 2. Table 2 Mean stability Sum of the 15 unit values Mean stability 15 to 18 “one” 19 to 37 “two” 38 to 56 “three” 5
39、7 to 74 “four” 75 “five” 8.2 Differential stability In some cases, however, it can be useful to note the stability of a surface active agent in hard water in terms of water hardness. For each of the three solutions S 1 ,S 2 and S 3 , and in increasing order of hardness, add the five unit values obta
40、ined and determine the partial stability for each solution as shown in Table 3. Table 3 Differential stability Sum of the five unit values for each sample of hard water Partial stability 5 or 6 one = 1 7 to 12 two = 2 13 to 18 three = 3 19 to 24 four = 4 25 five = 5 Three figures are thus obtained,
41、expressing the stability for each of the three hardness, 3 mmol/l, 4,5 mmol/l and 6 mmol/l, and characterizing the “differential stability”. The latter is, for example, 111 for the worst stability and 555 for the best stability in hard water. 9 Test report The test report shall include the following
42、 information: a) all details required for complete identification of the sample; b) the reference to this European Standard; c) the temperature of measurement; d) mean stability at t8C: one to five; e) differential stability at t8C: 111.555; f) any operation not included in this European Standard, o
43、r regarded as optional, as well as any circumstances which may have influenced the results; g) the date of the test.Page 5 EN 12458:1999 BSI 06-1999 Annex A (informative) Units used to express water hardness Name of units Definition Symbol Conversion factors Ca 2+ CaO CaCO 3 mmol/l meq/l 8d mg/kg a)
44、 8e 8a 8f millimole per litre 1 mmol of calcium ions (Ca 2+ ) in 1 l of water mmol/l 1 2,000 5,600 100 7,020 5,850 0 10,00 milliequivalent per litre 20,04 mg of calcium ions (Ca 2+ ) in 1 l of water meq/1 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
45、 l of water 8d 0,178 0,357 1 17,8 1,250 1,044 0 1,78 milligram per kilogram 1 mg of calcium carbonate (CaCO 3 ) in 1 l of water mg/kg a) 0,010 0,020 0,056 1 0,070 0,058 5 0,10 English degree of hardness 1 grain of calcium carbonate (CaCO 3 )i n 1 gal (UK) of water 8e 0,142 0,285 0,798 14,3 1 0,829 0
46、 1,43 American degree of hardness 1 grain of calcium carbonate (CaCO 3 )i n 1 gal (US) of water 8a 0,171 0,342 0,958 17,1 1,200 1 1,71 French degree of hardness 1 mol (= 100 g) of calcium carbonate (CaCO 3 )i n 10 m 3 of water 8f 0,100 0,200 0,560 10,0 0,702 0,585 0 1 a) The unit “part per million”
47、(ppm) is often used for mg/kg.BS EN 12458:1999 BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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49、s are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel: 020 8996 9000. Fax: 020 8996 7400. BSI offers members an individual upd
