A pure water sea

Title of the research project

DESAL - Computational Design of Nanoporous Materials for Water Desalination Mambranes 

Scientific area

Membranes, Computer Simulations, Graphene oxide

Project coordinator

Giancarlo Cicero

Abstract  

In this proposal, we explore a highly manufacturable form of ultra-thin nanoporous membranes for desalination. In particular, we strive to computationally investigate and optimize reduced graphene oxide (rGO) membranes for water filtration technologies as a potential low-cost nanoporous material.

Description of the research project 

Water desalination membranes work as molecular filters allowing water molecules to go through and rejecting the dissolved ion. The working principle is quite simple: an external pressure pushes a salty solution through the porous membrane and, if the pores in the membrane are small enough (in the nanoscale range) only the water molecules will pass thorough the membrane. Salt ions or other impurities are rejected.  At the end of the process, water collected on the other side of the membrane, is extremely pure. In this project we will employ different simulation methods to understand under which conditions it is possible to obtain porous reduced graphene oxide with controlled porosity.

The production of rGO from reducing graphene oxide (GO) is a highly complex process. In particular, with respect to water desalination applications, it would be desirable to understand exactly under what specific processing conditions the obtained rGO would be able to separate molecules. What is the best reduction environment to create nanopores in rGO in a controllable manner? What is the desired pore size in rGO for desalination? What are the ideal starting GO configurations to facilitate the formation of nanopores with desired pore sizes?

The computational approaches used during “DESAL” development will allow answering these questions. Our results will ultimately pave the way to the realization of extremely thin membranes characterized by high efficient desalination performance and economically more convenient than the one currently used in desalination plants.

Impact on society 

Today, desalinated water costs up to ten times more than typical groundwater. The energy footprint and operating cost of desalinated water via reverse osmosis is a direct function of the materials properties of the membranes and it is largely dominated by water permeability. The gains in cost of fresh water production with higher permeable membranes, as the one studied during this project development, would be important not only for the Italian industries but also for countries with sea access but scarce fresh water resources. Indeed, desalted seawater could be used both for drinking purposes and for agriculture applications.

Research results

The computational approaches used during “DESAL” development pave the way to the realization of extremely thin membranes characterized by high efficient desalination performance and economically more convenient than the one currently used in desalination plants.

In particular:

  • Protocol to realize single layer membrane with porous graphene
  • New collaboration with ENI
  • Collaborations with MIT- Massachusetts Institute of Technology and Imperial College
  • 3 new job positions at Politecnico di Torino

Working group 

At Politecnico di Torino:

Francesca Risplendi, Marco Laurenti

  • Budget: 148.675
  • Start date: 15/12/2015
  • End date: 14/12/2017