Dear Paularchos, 

I am having a hard time understanding what you are getting at; it sounds like a perpetual motion machine… 

There has been some research in the area of producing power from osmosis between salt water and fresh water. 

http7://phys.org/news/2016-07-electricity-salt-three-atoms-thick-membrane.html 

However, this does not use plasma. 

Perhaps you are thinking of enhancing the osmosis by charging the salt water? 

I am going to ask you something under private chat. 

Thanks 

Peter