Giving Compass' Take:

· Rice University has found a way to scale salt water purification by concentrating sunlight with the addition of inexpensive plastic lenses that bring in more light.

· What other advances have been made to scale the water purification process? 

· Check out this creation that has helped deliver clean drinking water to those in need.

Simply adding inexpensive plastic lenses to concentrate sunlight into “hot spots” boosted the efficiency of a solar-powered desalination system by more than 50 percent, researchers say.

“The typical way to boost performance in solar-driven systems is to add solar concentrators and bring in more light,” says Pratiksha Dongare, a graduate student in applied physics at Rice University’s Brown School of Engineering and co-lead author of a new paper in PNAS.

“The big difference here is that we’re using the same amount of light. We’ve shown it’s possible to inexpensively redistribute that power and dramatically increase the rate of purified water production.”

In conventional membrane distillation, hot, salty water is flowed across one side of a sheet-like membrane while cool, filtered water flows across the other. The temperature difference creates a difference in vapor pressure that drives water vapor from the heated side through the membrane toward the cooler, lower-pressure side.

Scaling up the technology is difficult because the temperature difference across the membrane—and the resulting output of clean water—decreases as the size of the membrane increases.

Read the full article about purifying salt water by Jade Boyd at Futurity.