Osmosis
is the process of water flowing through a semipermeable membrane from a
region of lower concentration to a region of higher concentration. A semipermeable
membrane is one in which only certain substances are allowed to pass through.
The driving force for osmosis to occur is to equilibrate the concentration
of the two solutions on either side of the membrane.
Dialysis
is similar to osmosis, but the dialyzing membrane allows small molecules
and ions to pass through as well as water. Larger particles such as colloids
can not pass through the dialyzing membrane. Thus dialysis would be an
efficient method for separating colloids from other particles in solution.