Engineers Use Nanotube Tech to Recover Fresh Water from Waste Brine

Engineers at the University of California, Riverside have developed a novel technique to recover nearly all water from brine waste. The discovery can help water-poor arid regions and also has industrial applications such as removing salinity form hydraulic tracking waste.

Reduced energy requirements, increased water recovery

By using a heating element that relies on carbon nanotubes, the researchers have devised a way that improves the recovery of fresh water during membrane distillation processes.

In situations dealing with brine solutions, membrane distillation is often used. Reverse osmosis is not an option because it cannot deal with high salinity solutions. Membrane distillation uses heat to drive water vapor across a membrane, allowing water to be recovered while salt remains. The process, however, is expensive because the heated brines are highly corrosive, driving up the cost of heat exchangers and other system elements. Also, the water recover is normally quite low — normally about 6 percent.

To improve recovery rates, researchers developed a self-heating carbon nanotube-based membrane that only heats the brine at the membrane surface. The new system reduced the heat needed in the process and increased the yield of recovered water to close to 100 percent.

To learn more about the researchers’ work, see their news release as well as their published work in Nature