You don't say how hot the humidity chamber is, its size and geometry , or how the 70% humidity got there in the first place (water/steam  injection?).  Why do you want to reduce the humidity to 10%? 10% is a very low humidity - much less than the surrounding ambient environment - even in a desert.  In my view, you'd need to condense out as much of the water as possible with an appropriate cold trap.  Then you could look at some form of high capacity and inexpensive drying agent such as silica gel.  For any reasonably sized humidity chamber this is still likely to be prohibitively expensive.  Why put the water into the chamber in the first place.  A dried air stream as intake to a closed humidity chamber seems to be the better route.  I used humidity chambers in the past the size of a large truck) at 85C/85% RH for semiconductor and display accelerated lifetime tests.

Great answer, Michael.  Akhilesh - see, from the list Michael posted, how few materials could be used to bring down the humidity...

Thanks to both of you sir..

Alan sir, actually I fabricate a humidity sensor and to characterize it I use a self made humidity chamber...

I just want to study the behavior of my sensor in low and high humidity. In beginning 69% humidity is the environmental humidity, I use mixture of glycerol and deionized water to increase its humidity level at fix temperature of 30 C.