Centre to design new ways to treat water

The University of Illinois has received a grant from the National Science Foundation to create a centre to develop advanced materials and technologies for water purification. The grant will provide US$4 million in funding annually for the first five years, with the possibility of a five-year renewal.

“The world is heading toward a severe water crisis,” said James Economy, Director of the new centre. “There are intelligence reports saying that within a decade or two, water – not food or fuel – will be the most serious shortage the world faces. The goal of the centre is to develop revolutionary materials and systems for safely and economically purifying water to counter the impending crisis.”

The centre will focus on improving disinfection and desalination processes, trace contaminant removal and the elimination of foulants that clog filters and reduce their effectiveness. It will also build upon carbon-fibre technology developed at Illinois, where glass fibre filters are tailor-made to optimise their adsorption of contaminants. The glass fabrics are activated through a chemical reaction that etches small pores into the carbon. The reaction determines both the pore structure and pore-surface chemistry, which control the adsorption properties of the filter.

“Our ability to tailor the pore size and surface chemistry of the fibres provides us with a unique capability to design highly selective systems for enhanced adsorption of specific contaminants, such as pesticides and chlorinated hydrocarbons,” Economy said. “Another family of ion exchange fibres has been developed that is extremely effective at removing trace metallic contaminants, such as lead, arsenic and mercury.”

New membranes being developed at the centre will have microchannels that could offer a low-cost alternative to the reverse osmosis process currently used in desalination. Scientists at the centre will also explore freeze distillation – the rapid crystallization and dissolution of water as a means of desalination.

Gas hydrates will also be investigated as a source of potable water. Found on the ocean bottom, these crystalline materials – or clathrates – form when water molecules create cage-like structures around other molecules such as methane, propane or isobutane. As clathrates form, the ocean’s salt separates out, offering a potential supply of fresh water. Scientists will explore ways of splitting these materials into clean drinking water and fuel.

“This program is intended to fill an enormous void that has developed over the past few decades where essentially no new materials have been developed for this important need,” James Economy told edie. “Part of the reason is that field of Civil Engineering has been responsible for addressing our needs for potable water, and the engineers in this field are not accustomed to solving their problems by designing new materials. Also, the companies that traditionally worked on such systems have ceased doing this kind of research as far back as the early 1970’s.”

The centre aims to design inexpensive filters capable of removing contaminants to well below parts per billion. “The goal is to be at least an order of magnitude below the current requirements of EPA,” Economy says. “Currently, there are no systems that function in these ranges in an economical manner.”

And along with improving on existing methods of desalination, the centre will explore new designs concepts such as the freeze distillation and clathrate techniques. “These have the potential of providing completely new approaches to the problem of low cost desalination,” continues Economy. “We also plan to design new kinds of highly efficient disinfectants which have the potential to destroy practically all the known bacteria.”