GRAPHENE FILTERS WITH TITANIUM. “The technology will never be strong enough to completely clean drinking water on its own. Rather, she sees it as a polishing step after traditional water treatment processes to mop up the most insidious pollutants.”
http://www.acs.org/content/acs/en/pressroom/newsreleases/2014/march/high-tech-materials-purify-water-with-sunlight.html