IS 3025-45: Methods of sampling and test (physical and chemical) for water and wastewater, Part 45: Sodium and potassium

16 Pages·1993·1.3 MB·English

by  Bureau of Indian Standards

इंटरनेट मानक
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in order to promote transparency and accountability in the working of every public authority,
and whereas the attached publication of the Bureau of Indian Standards is of particular interest
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timely dissemination of this information in an accurate manner to the public.
“जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न’ 5 तरफ”
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“The Right to Information, The Right to Live” “Step Out From the Old to the New”
IS 3025-45 (1993): Methods of sampling and test (physical
and chemical) for water and wastewater, Part 45: Sodium and
potassium [CHD 32: Environmental Protection and Waste
Management]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee””
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै”
Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”

IS 3025 (Part 45 ) : 1993
(Reaffirmed2003)

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Indian Standard
METH.ODS OF SAMPLING AND TEST
( PHYSICAL AND CI-IEMICAL ) FOR WATER
AND WASTEWATER
PART45 SODIUMAND POTASSIUM
(.. Fir~f)t Revision)
'l'hird Reprint SEP'rFI\t1AER 2007
(IncludingAmendment No. I)
uoc 6~8.11,3:543 I546.)) I
(i) HIS Il)l)]
BUR E A U OF I N D I A N S TAN DAR D S
MANAK 131-IAVAN~ 9 tll\l-IADlJl{ S~1AI-1 ZAFAR MAI{(,
NEW ()ELHI 110002
December 1993 Price(;roup 5
AMENDMENT NO. 1 APRIL 2003
TO
IS 3025 ( PART 45) : 1993 METHODS OF SAMPLING
AND TEST (PHYSICAL AND CH.:MICAL) FOR WATER
AND WASTE WATER
PART 45 SODIUM AND POTASSIUM
(FirstRevision )
(Page 3,clause5.6.2)- Substitutethe following for the existingequation:
'Forbracketingapproach, [(B-A.> (s-«) ~
sodium (orpotassium). mg/I = + A x D·
(b -a)
(CHD32)
Printed at:PrabhatOffsetPress. New Delhi-2
Environmental Protection Sectional Committee, CHD 012
FOREWORD
This Indian Standard ( First Revision) was adopted by the Bureau ofIndian Standards, after the
draft finalized by the Environmental Protection Sectional Committee had been approved by the
Chemical Division Council.
Industrial wastes invariably contain significant quantities of sodium. Sodium salts being
extremely soluble get leached early from soil and rocks and tend to remain in solution. .
Sodium is not particularly significant in potable water except for those having an abnormal
or
sodium metabolism. For high pressure boiler feed water even trace amounts of sodium are
concern.
Potassium rocks, such as silicates, are more soluble in water than sodium forms. Most natural
waters contains-less than 20 mgll ofpotassium, but watercontainingseveral hundred milligrams
per litre are occasionally found. Potassium is essential to animal nutrition.
In thepreparation of this standard. considerable assistance has been derived from standard
methods for the examination of water and waste water published by American Public Health
Association, Washington. USA, 16th edition, 1985.
The composition of the technical committee responsible for this preparation of the standard is
given in Annex A.
For the purpose ofdeciding whether a particular requirement of this standard is complied with,
the final value, observed or calculated" expressing the result ofa test or analysis, shall be rounded
offin accordance with IS 2: 1960 'Rules for rounding off numerical values (revised)'. The
number ofsignificant places retained in the rounded offvalue should be the same as that of the
specified value in this standard.
IS 3025( Part45) : 1993
Indian Standard
METHODS OF SAMPLING AND TEST
(PHYSICAL AND CHEMICAL) FOR WATER
AND WASTEWATER
PART 45 SODIUM AND POTASSIUM
( First Revision)
1 SCOPE 5 FLAME PHOTOMETRY METHOD
Thisstandard prescribesfollowing threemethods 5.1 PriacJple
for determination of sodium and potassium:
A flame photometer measures photoelectrically
a) flame emissionphotometric method using the intensity ofcolour imparted to the flame of
either a flame photometer or an atomic a Meker-type burner where the sample is
absorption spectrophotometer in the introduced into the flame under carefully
flame emission mode; standardizedconditions. The intensity ofcolour
is proportionaltothesodium/potassiumcontent
b) atomic absorption spectrometric method
in the sample. Sodium and potassium are
using an atomic absorption spectrophoto
determined at a wavelength of 589 nm and
meter in flame absorption mode; and
766·5 nm, respectively.
c) gravimetric method for determination of
sodium and colorimetric method for 5.2 Interferences
determination ofpotassium.
5.2.1 Radiation interference caused by elements
2 REFERENCES other than those being determined is the chief
contributing factor for error in flame photo
The IndianStandards listed below are necessary
metry. Of the elements encountered in these
adjuncts to this standard:
analyses, the major effect is due to interference
IS No. Title of one alkali-metal on another. Some effects
ape 'positive and some are negative, Among
3025 ( Part 1) : Methods of sampling and test the other common ions capable of causing
1986 ( physical and chemical) for interference are CI-, SO.I- and HC03- in
water and waste water: Part 1 relatively higher concentration. The foreign
Sampling (first revision) element effects cannot be'entirely compensated
7022 ( Part 1) : Glossary of terms relating to without employing calibration standards closely
1973 water, sewage and industrial duplicating the composition of the sample or
effluents, Part 1 by applying an experimentally determined
correction in those instances where the sample
7022 ( Part 2) : Glossary of terms relating to
contains a single important interference. How
1979 water, sewage and industrial
ever, the effects may be minimized by operating
effluents, Part 2
at the lowest practical sodium or potassium
concentration range or by removal of the
3 TERMINOLOGY
interfering elements, For example, aluminium
For the purpose of this standard, definitions has a depressingeffect on alkali-metal emission,
given in IS 7022 (Part 1) : 1973 and IS 7022 which may be of serious consequence. The
( Part 2 ) : 1979 shall apply. amount ofaluminium normally present in water
has been found to have a negligible effect on
4 SAMPLING AND STORAGE
alkali-metaldetermination. However,aluminium
The sampling and storage shall be done as in waste waters should be removed from the
prescribed in IS 3025 (Part I ) : 1986. Acidify solution prior to flame photometry if its
the sample to pH 2 with concentrated nitric concentration has been found by preliminary
acid. Store all samples/stock solutions in tests to exceed that of the alkali metal being
polyethylene bottles. determined.
1
IS 3025 ( Part 4S) : 1993
5.2.2 Self-absorption causes the curve of 5.4.2 Stock Potassium Solution
intensity versus concentration to decrease in
slope at higherconcentrationstending to reduce Dissolve in deionised distilled water 1·907g of
accuracy. Bracketing the unknown by known potassium chloride dried at 110°C. and make up
standard solution and inter-polaring linearly to t 000 ml with water, 1 ml == 1 mg of
potassium.
between the two minimizes this interference so
as to render it practically negligible. S.4.3 Standard Lithium Solution
5.2.3 Suspended matter which may interfere Weigh rapidJy 6·109 g of lithium chloride
mechanically by clogging the burner shall be (uci )or 9·93 g of lithium nitrate ( LiNO. )
removed by filtration prior to analysis. Organic dried overnight in an oven at 105°C.Dissolve
colouring matter docs not cause interference in water and make up to I 000 ml, 1ml = 1mg
and need not be removed. oflithium.
5.2.4 Flame photometers operating on the NOTE- Prepare a new calibrationcurve whenever
internal standard principle may require adding thestandard Iithium solution is changed.
a standard lithium solution to each working
5.5 Procedure
standard and sample. Follow the manufacturers
instructions for the optimum lithium concen S.5.1 Pretreatment ofPolluted Waler and Waste
tration. Water Samples
5.2.4.1 Incorporate a non-ionic detergent in the Take 100ml of sample in a beaker and add
standard lithium solution to assure proper 5 ml of concentrated nitric acid and evaporate
aspirator function when using the internal to dryness. Repeat this operation once again by
standard type flame photometer. adding concentrated nitric acid. Dissolve the
residue in minimum volume of concentrated
5.1.5 In the internal standard technique, pota
hydrochloric acid. Boil to dissolve, dilute to
ssium interferes with the sodium determination
50 ml with water, filter and make up to 100 mi.
ifthe potassium to sodium ratio is higher than
S : 1and sodium interferes with the potassium NOTE- No preliminary treatment of sample is
determination if the sodium to potassium ratio needed except filtration through an 11em ashless
filter paperof medium retentiveness jf the sample
is higher than 5: 1. Calcium interferes ifthe
contains only suspended rnatter as an impurity.
calcium to sodium/potassium ratio is higher
than 10: I. In such cases an approximate 5.5.2 Precautions
or
concentration the interfering ions may be Place the instrument away from direct sunlight
added to the sodium/potassium calibration or constant light emitted by an overhead fixture
standards. Magnesium interference does not in an area free of drafts. dust and tobacco
appear until magnesium to sodium/potassium smoke. Avoid contamination from corks, filter
ratio exceeds 100 : 1. paper, perspiration, soap, cleansers, cleaning
mixtures and inadequately rinsed apparatus.
S.3 Apparatus
5.5.3 Instrument Operation
5.3.1 Flame Photometer
Either direct-reading or internal standard type Follow manufacturer's instructions for selecting
or an atomic absorption spectrophotometer in proper photocell and wavelength, adjusting slit
the flame emission mode. width and sensitivity, appropriate fuel and air
or oxygen pressures and the steps for warm-up,
5.3.2 Glassware flame background, rinsing ofburner, aspirating
Rinse all glassware s with dilute nitric acid and igniting samples and measuring emission
( 1 : 15 ) followed by several portionsofdeioni intensity.
zed distilled water.
5.5.4 Direct-Intensity Meaaurement
5.4 Reagents
Preparea blankandsodium/potassiumstandards
Use deionized distilled water to prepare all in stepped amounts by diluting the stock solu
reagents, calibrations, standards and dilution tions described in 5.4.1 and 5.4.2 for any ofthe
water. following applicable ranges: 0 to 1·0 mgll, 0 to
10mg/l, or 0 to 100mg/l, so that within each
5.4.1 Stock Sodium Solution
range there are equally spaced standards in
Dissolve in deionised distilled water, 2·542 g of tenths of the maximum. Starting with the
sodium chloride dried to constant mass at highest calibration standard and working
140C.C and make up to 1000 ml with water. towards the most dilute standard, measure
1 ml = 1mg of sodium. emission at 589 nm for sodium and766·5 nm for
2
IS 3025 ( Part 45 ) : J993
,
potassium. Repeat the operation with both 6 ATOMIC ABSORPTION SPECTROMETRY
calibration standards and samples enough num METHOD
ber oftimes to secure a reliableaverage reading
6.1 Principle
for each solution.Constructa calibration curve,
byplotting emission intensity (scale reading) This method js hascd on the fact that when a
versusonconcentration ofeach calibration stan solution containing salts of sodium and potas
dard a linear graph paper. Preferably use the sium is introduced in the flame, the intensity of
bracketing approach described in 5.5.6. Deter the transmitted radiation will decrease in
mine sodium/potassium concentration of the proportion to the extent ofthe concentration of
sample solution from the respective calibration these clements in solution. A hollow cathode
curve. lamp made of the element to be determined
provides the sourceofradiation. The application
5.5.5 Internal-Standard Measurement
range ofthis method is 0·20 to 4·0 mg/l when
Add an appropriate volume ofstandard lithium using the 766·5 nm resonance tine for potassium
solution to carefully measured volume ofsample and 0·20 to 3·0 mg/l when using the 589·6 nm
( or diluted portion), each sodium/potassium resonance line for sodium.
calibration standard and the blank, and then
6.2 Interference
follow all the steps described in 5.5.4.
6.2.1 No chemical interferences have been
5.5.6 Bracketing Approach
found. Sodium and potassium are partially
From the calibration curve, select and prepare ionized in air-acetylene flame (to suppress
sodium/potassium standards that immediately ionization add potassium nitrate or potassium
bracket the emission intensity of the sample. chloride to give final concentration of2 000 p.gl
Determine emission intensities ofthe bracketing ml of potassium in the solution, itl which
standards (one standard slightly less and the sodium has to be measured and add anyone of
other slightly greater than the sample) and the the cesium nitrate, cesium chloride. sodium
sample as simultaneously as possible. Repeat nitrate and sodium chloride to give a final con
the determination on bracketing standards and centration of 1000 p.g/ml of cesium or 2 000
samples. ~g/ml of sodium as the case may be, in all
solutions including blank where potassium has
5.6 Calculation
to be measured). Presence of appreciable
5.6.1 For direct intensity measurement ( 5.5.4 ) coucentrations ofmineral acids in the solution,
and internal standard measurements ( 5.5.5. ) : reduce the absorbance reading for both sodium
and potassium. Hydrochloric acid, sulphuric
Sodium ( or potassium ), Sodium( or potas-
acid, nitric acid and phosphoric acid cause
mg/l = sium ) in mg/l in
decrease in the reading. Influence of nitric acid
portion x D
and sulphuric acid is mainly due to 'changes in
5.6.2 For bracketing physical properties and the aspiration rates of
approach s?dium (B-A)(s-a) the solution. The influence ofhvdrochloric acid
( or potassium), = ---- .--------+AX D and phosphoric acid is Que to the evaporation
mgjl ( b - a )
process in the flame.
where
6.1.2 Concentration of aluminium, phosphate,
B = sodium (or potassium) in upper sulphate and silicate up to 160 mgjl do not
bracketing standard, mg/I; interfere with low concentration of sodium,
A = sodium (or potassium) in lower namely, to 2 to 10 mg/}, But it is found that
bracketing standard, mg/}; slight decrease in absorption occurs in the
presence ofhigh concentration of phosphates.
b = emission intensity of upper bracketing
But the same amount of aluminium, phosphate,
standard;
sulphate and silicate do not interfere wirh
a = emission intensity of lower bracketing potassium, determination in the presence of
standard; aluminium chloride ( 1M ).
=
s emission intensity ofsample; and 1
6.3 Apparatus
I( sample in ml +
D = dilution ratio« distilled water in ml Atomic absorption spectrophotometer in the
L sample in ml J absorption mode, set up and operatedaccording
to the manufacturer's instructions, equipped
5.6.3 Repeat the calculation for the second set with an appropriate burner for air-acetylene
ofdata and average the two values to obtain flameand hollow cathode lamps for sodium and
the concentration ofsodium ( or potassium ). potassium determinations.
3
IS 3025( Part 45): 1993
6•.t ReageDts range shall be as below:
War.length, nm Working range, pglm!
6.4.1 POlalslum Chloride Solution
A r--.----A.----~
'Sodium Potassium Sodium Potassium
Dissolve 40 g ofpotassium chloride in distilled
water and make up to 1litre. 589·0 766·5 0·15 to 0·60 0·5 to 2-0
589-6 769·9 0-5 to 2·0 1-5to 6·0
6.4.2 Sodium Chloride Solution
330·2 ) 404.4
100 to 400 200to 800
Dissolve 50 g of sodium chloride in distilled 330·3 )
water and make up to 1 litre.
NOTE- By rotation of burner on S89 nm and
589·6om forsodiumand on 766·' nm and 769·9om
6•.t.3 Stock Sodium Solution - See 5.4.1.
for potassium, measurementscan be taken for 20 to
jOI4/m1. Ho\\'ever. the working range and also the
6.4.4 Stock Potassium Solution - See 5.4.1.
sensitivity may vary for different instrument
•pecification.
6•.t.5 StandardSodium Solution
'.5.5 Prepare calibration curve by plotting the
Take appropriate aliquots ofthe stock sodium absorbance reading against the sodium (or
solution ( 5.4.1 ) ina series of100 ml volumetric potassium) concentrations.
flasks to give a range of standard solutions in
6,,5.6 Aspirate the test solution and read the
the working range. Add 10 ml of potassium
sodium ( or potassium) concentration from the
chloride solution ( 6....1 ) and dilute to 100ml
calibration curve.
to have about 2000 p,g/I of potassium to supp
ress ionization while working in air-acetylene 6.7 Calculations
flame. Sodium (or Potassium). mgll = ex~1
6.4.6 StandardPotassium Solution
where
Take appropriate aliquots ofthe stock potas =
C: sodium (or potassium) concentration
sium solution (4.5.2) in a series of 100ml
from the calibration curve, mg/l,
volumetric flasks to give a range of standard
=
solutions in the working range. Add 10ml of Y volume oftheoriginal sample taken for
sodium chloride solution ( 6....2 ) and dilute to analysis, ml, and
100 ml to have about 20001£1/1 of sodium in VI= volumeofthe volumetricflask (100 ml).
the working solution.
7 GRAVIME1"RIC METHOD - FORSODIUM
'.5 Procedure 7.1 PriDclple
6.S.1 PreparationofSample Solution - See 5.5.1. Sodium is precipitated as sodium zinc uranyl
acetate hexahydrate, [ NaC.H.O•.Zn (C.H.O.)•.
6.5.2 Preparation ofTest Solutions
3UO. ( CIH~O. )1. 6H:lO] by adding a large
Take 10ml of the sample in a 100volumetric volume ofzinc uranyl acetate reagent previous
flask. Add 10ml ofpotassium chloride solution ly saturated with the sodium salt to a small
( 6.4.1) if sodium is to be determined and volume ofthe concentrated sample.
10ml of sodium chloride solution (6.4.2) if 7.1 IDterfereDce
potassium is to be determined. Make up to the
mark using distilled water. Lithium interferes by forming a slightly soluble
salt withthereagent,potassium interferesiCthere
6.5.3 Preparation of Blank Solution are more than 25mg in the I ml solution being
tested. Organic acids, such as oxalic, citric
Prepare appropriate blank solutions as in 6.4.5, and tartaric, interfere, as anions such as phos
6.4.6 and 6.5.1 usingthe sante reagentsand same phate that give precipitates with the reagent.
volume ofdistilled water instead of the sodium Sulphate must be absent when much potassium
( or potassium) solutions or the sample. is present because potassium sulphate is only
slightly soluble in the reagent. Ifthe potassium
6.5.4 Preparation ofCalibration Curves and sulphate concentrations are known, the
maximum possibleerrordue to theprecipitation
Aspirate the blank and calibration solutions of potassium sulphate can be calculated.
and aspirate distilled water in between. Carry Usually this error wiH be negligible because
out the measurements using an air-acetylene the potassium concentration in potable water
( oxidizing) flame. The wavelengthand working is low and also because the calculation factor,