EN 12926:2008

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Kemikalije, ki se uporabljajo za pripravo pitne vode - Natrijev peroksidisulfatProdukte zur Aufbereitung von Wasser für den menschlichen Gebrauch - NatriumperoxodisulfatProduits chimiques pour le traitement de l'eau destinée à la consommation humaine - Peroxodisulfate de sodiumChemicals used for treatment of water intended for human consumption - Sodium peroxodisulfate71.100.80Chemicals for purification of water13.060.20Pitna vodaDrinking waterICS:Ta slovenski standard je istoveten z:EN 12926:2008SIST EN 12926:2008en,fr,de01-december-2008SIST EN 12926:2008SLOVENSKI
STANDARDSIST EN 12926:20011DGRPHãþD

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 12926September 2008ICS 71.100.80Supersedes EN 12926:2000
English VersionChemicals used for treatment of water intended for humanconsumption - Sodium peroxodisulfateProduits chimiques pour le traitement de l'eau destinée à laconsommation humaine - Peroxodisulfate de sodiumProdukte zur Aufbereitung von Wasser für denmenschlichen Gebrauch - NatriumperoxodisulfatThis European Standard was approved by CEN on 30 July 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, 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 STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2008 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12926:2008: ESIST EN 12926:2008

General information on sodium peroxodisulfate.15 Annex B (normative)
General rules relating to safety.16 Annex C (normative)
Determination of arsenic, antimony and selenium (atomic absorption spectrometry hydride technique).17 Bibliography.23
1) Chemical Abstracts Service Registry Number 2) European Inventory of Existing Commercial Chemical Substances 3) 100 kPa = 1 bar SIST EN 12926:2008

4 Purity criteria 4.1 General This European Standard specifies the minimum purity requirements for sodium peroxodisulfate used for the treatment of water intended for human consumption. Limits are given for impurities commonly present in the product. Depending on the raw material and the manufacturing process other impurities may be present and, if so, this shall be notified to the user and when necessary to relevant authorities. NOTE Users of this product should check the national regulations in order to clarify whether it is of appropriate purity for treatment of water intended for human consumption, taking into account raw water quality, required dosage, contents of other impurities and additives used in the product not stated in the product standard. Limits have been given for impurities and chemicals parameters where these are likely to be present in significant quantities from the current production process and raw materials. If the production process or raw materials leads to significant quantities of impurities, by-products or additives being present, this shall be notified to the user. 4.2 Composition of commercial product The commercial product shall contain not less than 99 mass fraction percent of Na2S2O8. 4.3 Impurities and main by-products Sodium peroxodisulfate does not contain significant concentrations of impurities or by-products. SIST EN 12926:2008

Parameter
Limit in mg/kg of Na2S2O8
Type 1 Type 2 Arsenic (As) max. 0,05 5 Cadmium (Cd) max. 0,05 2 Chromium (Cr) max. 0,5 5 Mercury (Hg) max. 2 2 Nickel (Ni) max. 0,2 5 Lead (Pb) max. 0,05 5 Antimony (Sb) max. 5 10 Selenium (Se) max. 5 10 NOTE Cyanide, which does not exist in a strong oxidizing medium such as sodium peroxodisulfate, is not a relevant chemical parameter. Pesticides and polycyclic aromatic hydrocarbons are not by-products of the manufacturing process. 5 Test methods 5.1 Sampling Observe the recommendations of ISO 3165 and take account of ISO 6206. Prepare the laboratory sample(s) required by the relevant procedure described in ISO 8213. 5.2 Analysis NOTE All measurements should be made with a tolerance of ± 10% unless otherwise stated. 5.2.1 Determination of sodium peroxodisulfate (main product) 5.2.1.1 Principle Determination of peroxodisulfate content by back-titrating a predetermined excess of iron (ll) with potassium permanganate. 5.2.1.2 Reagents All reagents shall be of a recognized analytical grade and the water used shall conform to grade 3 in accordance with EN ISO 3696. 5.2.1.2.1 Potassium permanganate standard volumetric solution; c(KMnO4 ) = 0,02 mol/l. 5.2.1.2.2 Sulfuric acid (H2SO4), density ρ = 1,84 g/ml. SIST EN 12926:2008

0,1 mol/l. Dissolve 77 g of iron (II) ammonium sulfate in 500 ml water, add 150 ml of sulfuric acid (5.2.1.2.2) and 50 ml of phosphoric acid (5.2.1.2.3) and make up to 2 000 ml with water. Filter before use. 5.2.1.2.5 Potassium chloride (KCl). 5.2.1.2.6 Potassium chloride; c(KCl) = 3 mol/l. Dissolve 224 g potassium chloride (5.2.1.2.5) in water, add 2 ml of phosphoric acid (5.2.1.2.3) and make up to 1 000 ml with water. 5.2.1.3 Apparatus 5.2.1.3.1 Ordinary laboratory apparatus and glassware.
5.2.1.3.2 Automated potentiometric titration apparatus with program-control of the addition of the solution from the burette. 5.2.1.4 Procedure 5.2.1.4.1 Preparation of test solution Weigh, to the nearest of 0,1 mg, 0,30 g of sodium peroxodisulfate (m), transfer to a 250 ml glass beaker and dissolve with a small amount of water. 5.2.1.4.2 Determination Introduce the test solution (5.2.1.4.1) in the potentiometric titration apparatus (5.2.1.3.2). Add a predetermined excess of the iron (ll) sulfate solution (5.2.1.2.4) and titrate against the potassium permanganate standard volumetric solution (5.2.1.2.1). Record the volume (V) used. Carry out a blank determination, in duplicate, at the start of the determination and after ten titrations of test solutions. 5.2.1.5 Expression of results The sodium peroxodisulfate content, C1 , expressed as a mass fraction percentage is given by the following equation: ()mcVVC
000 105,119
1,0
01xxxxx−=
(1) where m is the mass in grams of the test portion; c is the actual concentration expressed in moles per litre of the permanganate standard volumetric solution; 0V is the volume in millilitres of the potassium permanganate standard volumetric solution used for the blank determination; SIST EN 12926:2008

(2) 5.2.2 Impurities Not applicable. 5.2.3 Chemical parameters 5.2.3.1 Determination of antimony (Sb), arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), nickel (Ni) and selenium (Se). 5.2.3.1.1 Principle The elements arsenic, antimony, cadmium, chromium, lead, nickel and selenium are determined by atomic absorption spectrometry. 5.2.3.1.2 Reagents All reagents shall be of a recognized analytical grade and the water used shall conform to the appropriate grade specified in EN ISO 3696. 5.2.3.1.2.1
Nitric acid, concentrated, density ρρρρ = 1,42 g/ml. 5.2.3.1.2.2
Nitric acid, solution c (HNO3) = 2,5 mol/l. 5.2.3.1.2.3
Barium nitrate, Ba (NO3)2. 5.2.3.1.3 Procedure 5.2.3.1.3.1 Test portion Weigh, to the nearest 0,01 g:  for Cd, Ni, Pb, As and Sb : 1 g (m1) of the laboratory sample into a 100 ml one-mark volumetric flask;  for Cr : 2 g (m1) of the laboratory sample into a 100 ml one-mark volumetric flask;  for Se : 0,5 g (m1) of the laboratory sample into a 100 ml one-mark volumetric flask. 5.2.3.1.3.2 Test solution For Cd: dissolve the test portion with 40 ml of water and after adding 20 ml of barium nitrate (5.2.3.1.2.3), bring solution briefly to boiling point and after cooling make up to the mark with water. The determination is made with the clear supernatant solution after the barium sulfate has settled out. For Cr and Ni: add 0,5 ml of nitric acid (5.2.3.1.2.2) to the test portion, dilute with a few millilitres of water and mix. Make up to the mark with water and homogenize. SIST EN 12926:2008

(3) where y is the interim result (5.2.3.1.3.3); V1 is the volume, expressed in millilitres, of the test solution (5.2.3.1.3.2) (= 100 ml); m1 is the mass, expressed in grams, of the test portion; C1 is the sodium peroxodisulfate content in mass fraction percent of product (5.2.1.5). 5.2.3.2 Determination of the mercury content (Hg) 5.2.3.2.1 Principle The element mercury is determined by flameless atomic absorption spectrometry in accordance with EN 1483. 5.2.3.2.2 Reagents All reagents shall be of a recognized analytical grade and the water used shall conform to the appropriate grade specified in EN ISO 3696. 5.2.3.2.2.1 Potassium permanganate solution, c(KMnO4) = 50 g/l. 5.2.3.2.2.2 Sulfuric acid, concentrated, density ρ = 1,84 g/ml. 5.2.3.2.2.3 Hydroxylammonium chloride solution, c(NH2OH.HCl) = 100 g/l. SIST EN 12926:2008

2A1×=y
(4) where yA is the result obtained in 5.2.3.2.3.3, for the concentration of mercury in the test solution, expressed in milligrams per litre; V2 is the volume in millilitres of the test solution. The mercury content, C4, in milligrams per kilogram of sodium peroxodisulfate is given by the following equation: 12214100CxmVxyC=
(5) where : y1 is the previously determined interim result for mercury content; V2 is the volume in millilitres, of the solution A (see 5.2.3.2.3.2); m2 is the mass, expressed in grams, of the test portion (5.2.3.2.3.1); C1 is the sodium peroxodisulfate content in mass fraction percent (5.2.1.5). SIST EN 12926:2008
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