AMTA NEWS Novel sub-nanofiltration ceramic membrane production uses DNA

A novel method for creating ceramic reverse osmosis membranes with sub-nanometre pores by using the genetic material, DNA, as a template former, overcomes the poor reproducibility encountered in conventional methods according to the developer of the technology, Cerahelix.

In a paper presented at this week’s AMTA and AWWA conference in Orlando, USA, lead author, Tyler J Kirkman, explained Cerahelix’s process as “Manipulating DNA as a generic – not genetic – material to produce a pore structure that is unique in nanoflitration membranes.”

The process exploits DNA’s property of aligning in a silica or titanium oxide sol gel to form columns. Once the sol gel is fired to form a ceramic membrane on an alumina support the DNA is burnt off to leave pores with diameters of less than 1 nm.

The combination of sub-nanometer pores in a hydrophilic material means that molecules can be separated by size, chemical properties and charge-charge interaction.” said Kirkman.

He claimed that the membrane had an “inherent resistance to fouling from organics.”

Adapting the process from silica to titanium oxide to increase chemical and hydrothermal resistance required modification to overcome cracking which increased the pore size. Tests on the titanium product “imply” that the technology could overcome the the high sulphate concentrations found in produced water waste.