Thinnest nanofiltration membrane to date

Jul 07, 2011
Thinnest nanofiltration membrane to date
Close-packed nanoparticle monolayers self-assembled from dodecanethiol-ligated gold nanocrystals. TEM image (left) and atomistic simulation of tryptophan transport through a pore.

A recent collaboration between researchers at the University of Chicago and the University of Illinois at Chicago with the Center for Nanoscale Material's Electronic & Magnetic Materials & Devices Group at the Argonne National Laboratory has produced the thinnest nanofiltration membrane achieved thus far, at about 30 nm, made of just four layers of nanoparticles.

A separation is a key component in both nanofiltration and reverse osmosis filtration systems. Typically they are microns-thick polymer films. Reducing the thickness of the membrane reduces the pressure that needs to be applied across the membrane in order to achieve a certain amount of flux, which is a major operational cost in these devices. The filtration coefficient of this membrane for aqueous solutions is two orders of magnitude larger than for typical polymer-based nanofiltration systems. Near only 80 kPa pressure, the membrane exhibits pronounced charge sensitivity for a variety of dyes and other molecules, while rejecting molecules greater than 1.7 nm in size. Guided by atomistic molecular dynamics simulations, it was found that molecular transport occurs through pore-like regions between close-packed nanoparticles and that dielectric exclusion dominates the charge-dependent rejection.

This research opens up new possibilities for using nanoparticles in nanofiltration and separation. As the particle size, surface ligand type, and packing geometry in the membrane can all be adjusted, it is potentially possible to further adjust the cut-off size and robustness of the membrane for a variety of filtration applications.

Explore further: Thinnest feasible nano-membrane produced

More information: J. Heet al., ”Diffusion and Filtration Properties of Gold Nanoparticle Membranes,” Nano Letters, 11, 243, (2011).

add to favorites email to friend print save as pdf

Related Stories

Better way to desalinate water discovered

Feb 09, 2006

Chemical engineer Kamalesh Sirkar, PhD, a distinguished professor at New Jersey Institute of Technology and an expert in membrane separation technology, is leading a team of researchers to develop a breakthrough method to ...

Nanopores make sterile filtration more reliable

Jul 01, 2010

Irregular pores, low flow rates: The plastic membrane filters used in sterile filtration do not always ensure that conditions are really sterile. Filter membranes of aluminum oxide are more reliable - the ...

Recommended for you

Thinnest feasible nano-membrane produced

Apr 17, 2014

A new nano-membrane made out of the 'super material' graphene is extremely light and breathable. Not only can this open the door to a new generation of functional waterproof clothing, but also to ultra-rapid filtration. The ...

Wiring up carbon-based electronics

Apr 17, 2014

Carbon-based nanostructures such as nanotubes, graphene sheets, and nanoribbons are unique building blocks showing versatile nanomechanical and nanoelectronic properties. These materials which are ordered ...

Making 'bucky-balls' in spin-out's sights

Apr 16, 2014

(Phys.org) —A new Oxford spin-out firm is targeting the difficult challenge of manufacturing fullerenes, known as 'bucky-balls' because of their spherical shape, a type of carbon nanomaterial which, like ...

User comments : 0

More news stories

'Exotic' material is like a switch when super thin

(Phys.org) —Ever-shrinking electronic devices could get down to atomic dimensions with the help of transition metal oxides, a class of materials that seems to have it all: superconductivity, magnetoresistance ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...