Hello! It all depends on Your research.

I would say, there are two options:

1) To centrifuge it;

2) To evaporate liquid.

Bonus option: to use electrophoresis

Hi,

it definitely depends on the size of your nanoparticles and how you want to use them in the next step. In general, you can centrifuge them or remove ethanol by evaporation. In order to avoid aggregation you might want to redisperse them into some other solvent.

Centrifugation at what speed and for how long?

use Stokes equation to calculate time necessary!

Use high speed centrrifuge

Dear Fatile,

The speed and time of centrifugation depend on your NPs type and centrifugation tube you use. If the NPs aggregation does not matter and tube is hard enough, you can proceed at higher speed like more than 15,000 rpm. But if you do not want aggregation you can use 6,000 to 10,000 rpm for 30 minutes or more. You need to check if the NPs and supernatant is completely isolated after centrifugation. If not, increase the time. I recommend you to keep 6,000 to 10,000 rpm but increase the time if needed for the proper separation. 

Use higher revolution per minutes, this will facilitate the separation

Lyophilisation of your nanoparticles can also be a good option.

Perhaps another option to look at is the use of dialysis tube if you want to extract ethanol and replace it by another solvent.

Depending of what material your particles are from, you can try to apply magnet for them

Magnetic nano particles can only be separated by using magnet as suggested by Olena. However, high speed centrifugation is the best method for separating nanoparticles.

Nanoparticles can be separated from aqueous solution by centrifugation process followed by decantation. The remnant of the liquid phase can be removed by heating at the boiling point of the liquid (in this case, the boiling point of ethanol) with constant monitoring.

Good Luck.

centrifugation will be the best way,

Centrifugal force is the best solution

The two methods above mentioned are suitable: evaporation of solvent or centrifugation.

thank you all for the meaningful contributions