Adding nanoparticles to a water purifying membrane can double its efficiency, according to a startup company based in Los Angeles. With global water usage on the increase and fresh water in limited supply, the company, NanoH2O, says its novel approach could make such purification technology a viable solution to a growing problem.
Reverse osmosis--feeding water through a semipermeable membrane to filter out impurities--is widely considered to be the most effective way to desalinate water. But it is very energy-intensive, and therefore expensive, because water has to be forced through the membrane under pressure. A key way to reduce the costs involved is to increase the water throughput for the same pressure. But for many years, improvements in membrane technology have been incremental at best, says Jeff Green, NanoH2O founder and CEO.
NanoH2O has found that adding porous nanoparticles to membranes can dramatically increase the efficiency with which water can be filtered. "Under similar pressure, twice as much water goes through," says Green. In a desalination plant, this increased permeability would reduce energy requirements by 20 percent, or increase water productivity by 70 percent for the same cost, he adds.