The Guardian wrote an illustrative report about nanotech advances to the cleaning of drinking water for the developing world, especially listing nanoparticles from magnetite, silver and titania:
SciDev.Net has summarized “nano-based products” like nanofiltration membranes, nanosponges, or nanorust that are “relevant to developing countries” for specific kinds of water treatments:
In the field of groundwater remediation, the use of zero-valent iron nanoparticles has already become quite popular. During the process, the particles are usually dissolved.
For example, Nanoiron s.r.o. applied their material at a groundwater remediation site in the Czech Republic. It eliminated chlorinated hydrocarbons and hexavalent chromium showing convincing quantitative results:
Lehigh Nanotech from Pennsylvania are listing former projects in which their iron nanoparticles were applied for environmental remediation all over the US:
Field trials have also been conducted in Ontario, Canada. A recent press release from Sydney explains how iron nanoparticles helped to clean Canadian groundwater that was contaminated with toxic chemicals. It could also become relevant to hundreds of Australian sites:
For TCE, a carcinogen from degreasers that contaminates goundwaters all over the world, a recent publication by Rice University has demonstrated that nanoparticles based on palladium clean TCE “a billion times faster” than iron-based reductants:
Even pollution with oil could be removed with the help of nanoparticles, as demonstrated recently by researchers from Genova. They used a polyurethane foam that can swim on water surfaces. Such foams were equipped with microspheres from PTFE (binding oil and repelling water) and nanoparticles from iron oxide (for a subsequent magnetic collection) to potentially bind and remove oil from contaminated water surfaces: