I think they used graphite in this paper...

http://www.sciencedirect.com/science/article/pii/S0003269712001029

That depends on the polysaccharide. The paper recommended above is actually for milk oligosaccharides, not polysaccharides, so your application may be different.  Charged polysaccharides are somewhat easier, because they can be purified by ion-exchange chromatography with pH or salt gradients. Neutral polysaccharides are a bit more challenging, but one method involves partial ethanol precipitation, followed by size-exclusion (gel filtration) chromatography. There are almost as many techniques as there are polysaccharides, so you will have to search the literature to find out how people working with similar polysaccharides have proceeded.

Your question looks very broad. What is/are your specific plysacharide(s)? Do you have idea about the structure and physico-chemical properties of your polysacharides? I agree with Greg. The physico-chemical properties of your polysacharides should be considered to develop an efficient method for purification of polysacharides. 

@Greg Cote @ Alemu Tekewe 

I have extracted crude polysaccharide from Dictyophora indusiata mushroom and further I want to purify it. surely i will go through the literature to get the relevant protocol.Thanks for your suggestions :) 

@Kou Hayakawa . Thank you so much for your suggestion.:)

Dr Sadia

You can also consider the following publications....

Cheers....

Thank you Thomson.....

Dear colleague,

I proposed high-performance size-exclusion chromatography .

also  i hope the attached file was helpful.

@Mahboubeh Saeidi  ,Thank you so much :)