the main principle is synthesis material characterized by small size than the big same material which called bulk also the nano particles have specific surface area(SSA) so the nano particles more activity than bulk, the synthesis by 2 ways
up to down or up to top.
these materials enter in vet.and humen medicine ,agreculture,engeeniring also in an enviroment and treated wastwater .
As a research assistant in the field of water treatment, I could talk about my field. Let's talk about filters. You can filtrate water with some macro-scaled stones or other stuffs with conventional technology. However, it does not mean that it will be safe to drink it. Would you drink a cup of seawater after you filtrate it? Surely not.. However, nano-technology offers are to create nanopores which can filtrate even seawater ions. (which we call as desalination membranes). Bests..