  Water desalination through nanopores has been shown to be a promising
alternative to the currently water purification processes. In spite the results
in this direction obtained by means of computational simulations were animating
there are still pending issues to be resolved. For example, water desalination
involves macro numbers (in size and time) but in such a scale it is literally
impossible to attack this problem using all-atoms simulations. It is common to
extrapolate results from nano to macro sizes in order to estimate quantities of
interest, which must be taken with care. Here we present a simple model which
mimics the separation of salt from water, which may help to attack bigger
problems on water desalination subjects. Besides, we show that the
investigation of a restrict space of parameters imposed by expensive models may
hidden interesting, important features involved in the water desalination
problem. Finally, we present an analytical calculation which explains the rich
behaviour of the water flux through nanopores in a water-salt separation
scenario.
