ANALYSIS OF LOW AND HIGH SILICA IN WATER

Ammonium Molybdate Solution 

(I) Add 2 ml of conc. H2SO4 (Sulphuric acid) carefully to 100 ml of demineralised water.

(ii) Dissolve 25 gms of ammonium molybdate in 100 cc of demineralised water. Mix (i) and (ii) and make up the volume to 333 ml.

10% Oxalic Acid:

Dissolve 25 gm of oxalic acid in 250 ml of demineralised water.

A.N.S. Solution :

i)Take 3.5 gm of sodium sulphite in a dry mortar and add 0.375 gm        1- Amino - 2 naphthol 4- sulphonic acid (A.N.S.) to it and grind well. Mix this in 50 ml of demineralised water 

ii)Add 22.5 of sodium sulphite to 200 ml demineralised water and mix well. Mix solutions (i) and (ii) .

Take 50 ml water sample in a 100 ml beaker.

Add 2 ml of Ammonium molydate solution prepared (as in 6.1) wait for 2 minutes .

Add 4 ml of oxalic acid (6.2) and 1 ml of A.N.S. solution (6.3) without any time gap. Without any time gap. Wait for 4 minutes.

The developed blue colour is matched or measured with the known value of low silica standard developed in the same manner at 815 mm.

ANALYSIS OF HIGH SILICA IN WATER

Ammonium Molybdate Solution (10%):

Dissolve 10 gm of Ammonium molybdate in 100 cc of demineralised water. 

HCl Solution (1:1):

Add 100 ml of A.R. quality HCl carefully in 100 ml of demineralised water and then cool it.

Oxalic Acid (10%):

Dissolve 10 gms of oxalic acid in 100 ml of demineralised water.

A.N.S. Solution:

a) Mix 0.5 gm of A.N.S. (1-Amino 2-Naphthol 4-Sulphonic acid) and 1 gm of sodium sulphite and grind it to homogenity and then mix with 50 ml of demineralised water.

b) Add 30 gm of sodium Bisluphite in 100 ml of demineralised water. Now mix solutions (a) and (b) and make up the volume to 200 ml with demineralised water.

In a 100 ml beaker take 25 ml of sample and 25 ml of demineralised water shake gently for mixing.

Add 1ml of HCl (prepared as in 7.2), 2 ml of ammonium molybdate (7.1). Shake a little and wait for 2 minutes.

Add 2 ml of oxalic acid (7.3), 2 ml of A.N.S. Solution (7.4). Shake gently and wait for 4 minutes.

Measure the colour of the developed solution with a photocolorimeter at a wave length 650 mm.

ANALYSIS TO TSS AND TDS OF WATER

Method for T.S.S. (Total Suspended Solids)

Instrument  - Nephelometer

Turbdity standard:

Solution I: Dissolve 1.00 gm Hydrazine Sulphate (NH2)2 SO4 in the demineralised water and dilute to 100 ml in a volumetric flask.

Solution II : Dissolve 10 gms hexamethylene tetramine (Hexamine ) in demineralised water and dilute to 100 ml in a volumetric flask.

Standard 400 N.T.U: 

(Nephel Turbidity Unit): In a 100 ml volumetric flask mix 5 ml of solution I with 5ml of solution II. Allow to stand for 24 hours at 25 - 30C, then dilute to the mark and mix .The turbidity of this suspension is 400 N.T.U.

Standard 100 N.T.U. : 

In a 100 ml volumetric flask take 25 ml of 400 N.T.U. standard solution and dilute with water to the mark.

Adjust the instrument first for zero N.T.U. by taking demineralised water in the nessler tube and adjust to the zero with the set zero knob. Then adjusted for 100 N.T.U. by taking std.100 N.T.U. solution in the nessler  tube and adjust to 100 with set 100 knob.Then take the water sample in the nessler tube and measures the deflection on the scale.

Results : 

The deflection value x 1.55 = T.S.S. ppm (parts per million) 

Methods for T.D.S. (Total Dissolve Solids)

Instrument :

Conductivity meter. Calibrate the conductivity meter with a known standard pottasium chloride solution (.01m) whose conductivity at 25C is 1408/mho/cm.

Procedure : 

Take the water sample in a beaker. Place the conductivity cell after washing it with demineralised water and then with the sample. Take the reading of conductivity on the display screen. Take the temperature of the sample with the help of thermometer. From the temperature correction chart (Annexure - 1) find out the factor at that temperature. Factor multiply by the reading gives the conductivity of the sample at 25 C.

Result : 

Conductivity of the sample x 2 =   ----- = T.D.S.(p.p.m) Parts per million

The result of the TSS and TDS (in ppm) of water sample is reported to the concerning departments in respective pen duplicate.