People who have heard me speak know I am very interested in applications of nanotechnology to bring potable water to the developing world. Indeed, recent interest from the Bill and Melinda Gates Foundation indicates this may be a contemporary applications worth notice given the millions of children who suffer and die from water-borne parasitic and viral diseases. Their web site reports: In the developing world, severe diarrhea is a killer, taking the lives of between 2 million and 3 million children every year. Persistent cases of diarrhea cause malnutrition, retard growth, and delay mental development."
According to their web site (http://www.gatesfoundation.org/GlobalHealth/Pri_Diseases/ADI/default.htm):
"The foundation focuses support on efforts to:
- Prevent acute diarrheal illnesses through the development of vaccines against their major causes
- Develop drugs to stop life-threatening dehydration in children with infectious diarrhea
- Increase knowledge of the causes of acute diarrheal illnesses to improve diagnostic tools and treatment
- Discover new tools and strategies to treat severe diarrhea."
The report discussed applications for water treatment, esp. those associated with point of use (POU) in the three general classes: filters, membranes, and catalysts. In addition, the report covers nanoparticles for groundwater remediation. While much of this information is self-reported (from corporate public relations and marketing professionals), it still can be a useful guide to water treatment nanotechnologies.
It is particularly interesting to read this report with the understanding that when we are discussing water treatment, we seldom are comparing one method to another. Instead, there is a layering of technologies which can be used. For example, POU ceramic filters might be enhanced with colloidal silver supplementing a community based remediation technology.
Chapter 2 deals with Nanotechnology-Based Water Treatment Technologies. It begins with a review of carbon nanotube-based (CNT) membranes and Seldon Labs' nanomesh. In the category of nanofiltration, we get coverages of Saehan Industries' nanofiltration membranes, Argoinide's NanoCeram alumina nanofilters, and KX Industries' World Filters. In the category of nanoporous ceramics, clays, etc., we read about Porous Ceramic Shapes and MetaMateria's Cell-Pore, Nanovation AG's Nanopore (ceramic nanopowders on a support material), Pacific Northwest Lab's SAMMS (ceramic nanoscale pores with a monolayer on mesoporous supports), SolmetexX Inc.'s ArxenX (hydrous iron oxide nanoparticles on a polymer substrate), Cyclodextrin's polymer for POU and in situ groundwater treatment, and Pacific Northwest Lab's CNT nanocomposites (a thin film of an absorbent powder on a matrix of CNTs). The chapter also covers zeolites like AgION Technologies Inc.'s zeolite-silver compounds. In the category of nanocatalysts, we get a review (though superficial) of nanoscale zero valent iron, titanium dioxide photocatalysts, Adsorbia GTO's titanium oxide nanoparticle adsorbent, and Adedge Technologies, Inc.'s AD33 (nanostructured iron oxide metal for arsenic removal, and NanoMagentics, Ltd.'s MagnetoFerritin.
A short report well worth your time.
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