The most common method is freeze drying... However, you can try drying one of these methods; spray drying or microwave drying. These might help.

Dear Rahul..

Drying in an oven at lower temperature (60 - 80 oC) for longer period of time (more than 24 hours) can also result in powder. However, sometimes this will result in a thick viscous product depending on the hydrophilic nature of your CDs. Especially when you are using ethylenediamine for the synthesis of CDs, you will get this kind of viscous matter.

All the best..

thanks dear sir Rajkumar Bandi

but the problem still persisting.