A man is lost at sea. This scenario rarely ends in a casualty due to starvation or shark attack, but the lack of drinking water. It is a sad irony to die of thirst when so much water surrounds you.
With today’s desalination technology, however, the next bottle of water you guzzle down may very well have originated in the ocean. Water purification research with the use of membranes and reverse osmosis has been underway since the 60′s. Contaminated water is forced through this semi-permeable membrane which allows water to pass through but all contaminants such as salt and bacteria are left behind.
Water purification plants use this technology worldwide, but the high cost of desalination has kept it from being used as much as it could be. It can cost upwards of $1,000 to desalinate an acre-foot of seawater. This is roughly the amount of water 1-3 suburban families use per year. Compared to the $200 per acre foot it costs to filter water from other sources, desalinization does seem costly.
Fortunately, NanoH2O has developed a membrane that reduces costs and increases efficiency of the reverse osmosis filtration process. According to the NanoH2O website “NanoH2O enhances current polymer-based membranes with nanostructured material that allows additional ‘degrees of freedom’ in the control of membrane properties. The result is a wide array of advantageous membrane characteristics including improved permeability while maintaining requisite salt and contaminant rejection, both passive and active fouling resistance, as well as ‘tunable’ membrane performance to address specific water chemistries.”
Developed at UCLA, these membranes are developed at the nanoscale with tunnels a molecule thick and particles incorporated into the membrane that help the osmosis process! In an article published by UCLA, Engineering professor Eric Hoek describes the technology he helped create : “The nanoparticles are designed to attract water and are highly porous, soaking up water like a sponge, while repelling dissolved salts and other impurities,” Hoek said. “The water-loving nanoparticles embedded in our membrane also repel organics and bacteria, which tend to clog up conventional membranes over time.”
The article continues explaining that “Initial tests suggest the new membranes have up to twice the productivity — or consume 50 percent less energy — reducing the total expense of desalinated water by as much as 25 percent. ”
The entire article can be viewed at: http://www.newsroom.ucla.edu/portal/ucla/Today-s-Seawater-Is-Tomorrow-s-7410.aspx?RelNum=7410
This is promising, especially since seawater is such an abundant resource that many coastal third world countries would benefit immensely from using through this technology. Who knows, the ocean might be even more refreshing than you think.