[Sbaraka]

so another High school experiment where we have to remove tannins from water. (we are given tea water and have to remove the tea.)
so far me and my group have used Alum (aluminium potassium sulfate), which worked pretty well after the addition of some lime water, but it didn't work as well as we would like. next we used anion resin, which worked extremely well in terms of removing all the colour from the water, however due to the chemical we used to charge the resin (sodium hydroxide i think it was), its not exactly good water anymore (its got a foul smell, and has a slimy soapy feel to it).

so now we are looking into oxidising agents, however we are having trouble finding which chemical to use as an oxidising agent, so the question i ask is can anybody give me more information or refer me to somewhere where i can find more information on oxidising agents for cleaning water. (so far all i can find is stuff about bleach, and yea...)

[MOTOBALL]

This should be possible by,

1) passage through a column of silica gel (test using a pasteur pipette filled with silica gel and plugged with glass- or cotton-wool)

or

2) filtration through a bed of activated charcoal (or even just stirring with it).

[Sbaraka]

yea we have used the activated charcoal, it worked really well, but i just remembered another key point.

our task is to find qualitatively a way to remove the tannins, but then we have to find out quantitatively how much we need of solution X to remove the tannins.

and activated charcoal isn't really good at that.... because the teacher wants us to find something that can be solved quantitatively via titration. so any other clues?

[MOTOBALL]

I think we need to clarify the objective here.

1). If removing the tannins is the objective, then a chromatographic procedure or adsorption onto activated charcoal as described would work.

Alternatively, filtration of the coagulated tannins (no idea how to coagulate) would remove them.

2). However, use of an oxidizing solution will NOT remove them; it will merely bleach (decolorize) them (maybe) into invisibility.

If (2) is the objective and the resultant "tea" is to be drinkable, then hydrogen peroxide solution (H2O2) from the pharmacist may be suitable.  Peroxide solution is usually either 10% or 30%, I cannot remember.  CAUTION, you do NOT want to drink undiluted peroxide, NOR do you want it splashing in your  eyes !!!!!!!

I suggest that, in a small-scale trial,  you add 1 volume of H2O2 to 10 volumes of tea. If Tea is not decolorized, add another 1 vol. of H2O2 etc. If the tea does become decolorized at some point, you may still have residual H2O2 present.  This will be decomposed to oxygen and water by boiling your solution.

[Sbaraka]

yea i found Hydrogen Peroxide, but becuase, like you said, it is a harmful chemical, i was hoping to find something else. but none the less you have persuaded me to give it a try and i'll see what our teacher says about it.

thanks for the help and hopefully we can find something else. or something