Water purification system shows potential

Process developed at UT-Austin could help during disasters

After Hurricane Harvey spewed contaminated water into Houstonians drinking water systems, many had no choice but to flush them with bleach and hope for the best.

But one University of Texas-Austin researcher thinks he has a better solution for residents in that situation: an inexpensive, inhome water purification system that uses a jelly-like substance and natural sunlight.

In a paper recently published in the journal Nature Nanotechnology , Guihua Yu, a UT-Austin associate professor of materials science and mechanical engineering, outlines this technology, which he began developing two years ago.

Essentially, this jelly-like substance — called a hydrogel — is placed in contaminated or salty water and exposed to natural sunlight.

As both the water and the gel heat up, water vapor begins to rise up through the hydrogel, where any salt or contaminants are separated.

The vapor is then captured by a water condenser, where it converted back into water — only this time it is clean and safe to drink.

Though similar techniques are used to treat water already, Yu and his colleagues say their approach is much more cost effective because it relies solely on solar energy.

“Existing solar steaming technologies used to treat saltwater involve a very costly process that relies on optical instruments to concentrate sunlight,” an April UT-Austin news release stated. “The UT Austin team developed nanostructured gels that require far less energy, only needing naturally occurring levels of ambient sunlight to run while also being capable of significantly increasing the volume of water that can be evaporated.”

When asked for a cost comparison, Yu could not provide one.

Tests of these new hydrogels showed that up to 25 liters per square meter of water could be purified through the process, which Yu said would definitely be enough for a family in the aftermath of a storm, like Harvey, that severely contaminated their water.

“When a household needs freshwater due to a breakage, if a household has effective water evaporating materials, they can produce clean water easily at home,” Yu said.

Yu currently has a patent pending on this technology, he said, and is working on commercializing it.

He said he believes the technology will be available for households in fewer than five years.

But his team has plans to build out the technology on a much larger scale, to purify water for whole communities.

“I believe we can potentially go beyond the household because these materials are much more effective,” he said. “The hydrogels can easily be retrofitted to replace the core components in most existing solar desalination systems, thereby eliminating the need for a complete overhaul of desalination systems already in use.”

“I believe we can potentially go beyond the household because these materials are much more effective.”

Guihua Yu, UT-Austin associate professor