Stanford Researchers Create a Low Powered Water Filter Made of Cotton and a Solution of Carbon Nanotubes and Silver Nanowires

Definitions:

Nanotube- A hollow cylindrical  molecule made of one element, usually carbon.


Circumvent- To go around


Biofouling- The impairment or degradation of underwater surfaces or equipment as a result of the growth of living organisms.

Silver Nanowires A microscope image shows the

silver nanowires in which the cotton cloth is dipped. 

Courtesy of Yi Cui, Stanford University

  

                                                        

                                                                                                    

Summary:

A Stanford Research team has found a simple, cheap, and efficient way to filter water using cotton dipped in a solution of carbon nanotubes and silver nanowires. They made this filter to solve a severe problem in the world today. Many developing countries and countries plagued with natural disasters often have very little to no clean water. Therefore, they use water filters, which often filter using tiny pores which the water flows through to get rid of bacteria . These filters have three problems; they are slow, often need  lots of electricity, which is a scarce resource in these countries, and are susceptible to biofouling, which in this case would be bacteria clogging the pores. The Stanford team’s filter circumvents most of these problems by simply letting the bacteria pass freely through the filter, zapping the bacteria with a lethal amount of volts.  The filter that was able to kill 98 percent of Escherichia coli bacteria in water with a minute 20 volts of electricity, much less than the electricity required in normal filter pumps. Carbon nanotubes were used because they are efficient conductors of electricity, and silver has bacteria-killing chemical properties. These Stanford researchers have achieved a miracle. They have created water filter that is cheap, efficient, and fast.

Discussion:
This water filter is practical for people in developing countries or countries plagued by natural disasters. It's materials, cotton, a negligible amount of silver, and carbon nanotubes, is quite cheap and practical for people living in these areas. This water filter is an amazing device which will hopefully soon supply water for people who are in dire need of fresh water.

Questions:

1) This water filter filters out bacteria, but does it also filter out debris and other sediments found in water?

2) How would people get a hold on the silver nanowires and carbon nanotubes?

3) How can this filter be improved so the 98% of bacteria killed becomes greater like a 100%?

Citations: 

Article: http://www.popsci.com/science/article/2010-08/cotton-filter-soaked-nanotech-cheaply-and-quickly-purifies-large-volumes-water

Picture of Water:  http://www.scholastic.com/safewater/images/rightColumn/clean_water.jpg 

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