GB / T 12496.8-1999 wooden activated carbon -- Determination of iodine adsorption value

1. principle

Take a certain amount of sample and iodine solution, mix and vibrate fully, absorb the filtered solution, titrate it with sodium thiosulfate standard solution, calculate the residual iodine content in the solution according to the formula, and express the adsorption value of activated carbon for iodine.

2. steps

A. reagent

① Iodine (analytical pure);

② Potassium iodide (analytical pure);

③ Sodium thiosulfate (analytical pure);

④ Soluble starch;

⑤ Potassium dichromate (Reference Reagent).

b. Standard solution

① 0.1mol/l iodine standard solution;

② 0.1mol/l flow substitute sodium sulfate solution;

③ 1% starch solution.

C. Operation steps

① Weigh and take 0.5g of dry test crushed to 71um (weigh to 0.4mg, if the powder carbon and granular carbon are not fine enough, they need to be fully ground to meet the requirements below 71um.) Put it into a dry 250ml iodine measuring bottle, add 50ml0.1mol/l iodine standard solution, immediately cover the bottle plug, vibrate on the oscillator for 15min, and then filter it into the drying beaker quickly;

② Use 10ml pipette to suck 10ml filtrate and put it into 250ml iodine volumetric flask, use 0.1mol/l flow substitute sulfuric acid standard solution for titration, when the solution is light yellow, add 2ml starch indicator solution, continue titration to make the solution colorless, record the volume of sodium thiosulfate consumed, and calculate the content of iodine adsorption value according to the formula.

D. computing

A＝5×127（10C1－C2V2）/m

Formula:

A -- iodine adsorption value of the sample, mg / g;

C1 -- concentration of iodine standard solution, mol / L;

C2 -- concentration of sodium thiosulfate standard solution, mol / L;

V2 -- volume consumed by sodium thiosulfate standard solution, ml;

M -- weigh the mass of the sample, G.