A new thin film nanocomposite that can dramatically increase the permeability of a reverse osmosis membrane. The process involves a thin polyamide film with relatively hydrophobic pores periodically interrupted by nanoparticles having super-hydrophilic pores. While water diffuses through the polyamide pores only under high applied pressure, water penetrates through the nanoparticle pores with very little applied pressure. Because the nanoparticle pore walls are even more negatively charged than the membrane surface, ion exclusion is enhanced in concert with increased water permeability.

The super-hydrophilic nanoparticles also enhance fouling resistance by making the overall membrane more hydrophilic. Not only can water’s permeability be increased by 75%, but the new membrane has improved rejection characteristics. The concept was developed by Dr Eric Hoek at UCLA. It is being commercialized by NanoH₂O. If the performance of nanocomposite membranes in the laboratory can be replicated on a commercial scale, they could cut the cost of desalinated water by a significant margin. Nanocomposite technology promises the first major step forward in the core reverse osmosis process for some years.

Judges’ Verdict:

Nanocomposite technology promises the first major step forward in the core reverse osmosis process for some years.