# Determination of Iodine Value of Activated Carbon

Apparatus:

beaker,

burette,

pipette,

filter paper

Reagents:

* 0.1N Iodine solution ( 40 gm KI in 1 Ltr of Distilled water ).

* 0.05N Sodium Thiosulphate solution (12.5 gm Na2S2O3.5H2O in 1 Ltr Distilled water)

* 1% Starch solution

* Activated carbon

Procedure:

I Standardisation of Iodine solution

* Take 10c.c of 0.1N Iodine solution in conical flask.

* Add 2 drops of Starch solution.

* The pale yellow colour of Iodine Soln turns Blue.

* Titrate with 0.05 N Sodium Thiosulphate till it becomes Colourless.

II

* Weigh very accurately 0.2 gm of Activated carbon

* Introduce it into the Iodine flask which should be completely dry

* Add 40cc of 0.1N Iodine solution

* Shake the flask for 4 minutes and filter it

* Collect the filterate in a dry flask and Titrate 10cc of the filtrate against

Standard Sodium thiosulphate solution using starch as indicator

* Burette reading corresponds to (A)

Calculations:

Iodine value: C x Conversion factor; mg/gm

Factor:Mol wt. of iodine (127) x normality of iodine x 40 / Wt. of carbon x Blank reading

C=B-A

Note: Iodine test should be performed on dry basis

Carbon should be dried in oven at 110oC for three hours before weighing

Iodine value is expressed in mg/gm of carbon

### 5 throughts on "Determination of Iodine Value of Activated Carbon"

1. Ernest says:

Gud day.I saw another formula about the iodine value of activated carbon,that they are using a conversion factor in the computation of iodine.The conversion factor depends on the normality of the filtrate?Is it the same with your formula?thanks

2. Todorjan says:

I’ve 2 questions for you regarding the determination of the value of iodine in powdered activated carbon:
1-(Collect the filterate in a dry flask and Titrate 10cc of the filtrate against
Standard Sodium thiosulphate solution using starch as indicator)
This sentence, I do not understand please can you tell me more clearly?
2-How to prepare 1% Starch solution in the form of liquid because of the starch in the form of a solid?

1. Take 100 ml distilled water in beaker and boil. Add preferably soluble starch to boiling water. Stop heating and stir .cool the sole and use

3. Noemi says:

Just one question, where does the 40 come from in the conversion factor and does it have units?

4. Tushar ratani says:

I tried same but I didn’t get Perl yellow colour of potassium iodine solution and not even blue color after add 2 drops of 1%starch solution.
I can’t understand what mistakes I had done . Please reply with exactly how to make potassium iodine solution with point need to care about like sunlight and storage.