Nanofilters: pure water without deception
A method of disinfection of water using nanostructures is proposedDmitry Safin, Compulenta
At Stanford University (USA), a model of a filter made of cotton fabric with the addition of nanowires and nanotubes designed for water disinfection was made.
Well-known versions of filters that mechanically detain microorganisms pass water quite slowly; in addition, the liquid has to be supplied under pressure, and this requires additional equipment and increases electricity consumption. The new model, according to the authors, works about 80,000 times faster, demonstrating the throughput of one square meter of fabric equal to 100 cubic meters per hour. At the same time, water can flow naturally, under the influence of gravity.
Silver nanowires in the structure of the fabric to which large fibers belong
(illustration by the authors of the work).
The filter is based on ordinary cotton fabric, which is immersed for a few minutes in a solution of silver nanowires (precious metal takes very little to produce them, scientists say) and carbon nanotubes. The diameter of the latter reached up to one nanometer, and their length was measured in units of micrometers, while nanowires with a diameter of 40-100 nm were stretched to 10 microns. After such treatment, the fabric acquires excellent conductive properties.
The disinfecting effect is given by passing a small current. The filter can be powered by a compact solar battery or two 12-volt car batteries. In experiments with Escherichia coli bacteria, a filter about 6.5 cm thick reduced the concentration of microorganisms by more than 98%.
In the near future, the researchers plan to conduct experiments with other types of bacteria.
Comparison of the effectiveness of the filter option described above
and its "lightweight" modifications (illustration by the authors of the work).
The full version of the report will be published in the journal Nano Letters (David T. Schoen et al., High Speed Water Sterilization Using One-Dimensional Nanostructures).
Prepared based on materials from Stanford University (High-speed filter uses electrified nanostructures to purify water at low cost).
Portal "Eternal youth" http://vechnayamolodost.ru01.09.2010