{"page":"\u003clink rel=\"stylesheet\" href=\"https://lessonplanet.com/assets/packs/css/resources-c03aa079.css\" /\u003e\n\u003clink rel=\"stylesheet\" href=\"https://lessonplanet.com/assets/packs/css/lp_boclips_stylesheets-517835be.css\" media=\"all\" /\u003e\n\u003cdiv data-title='Scientist develop new water filter' data-url='/boclips/videos/5c54c08ed8eafeecae14ba2d' data-video-url='/boclips/videos/5c54c08ed8eafeecae14ba2d' id='bo_player_modal'\u003e\n\u003cdiv class='boclips-resource-page modal-dialog panel-container'\u003e\n\u003cdiv class='react-notifications-root'\u003e\u003c/div\u003e\n\u003cdiv class='rp-header'\u003e\n\u003cdiv class='rp-type'\u003e\n\u003ci aria-hidden='true' class='fai fa-regular fa-circle-play'\u003e\u003c/i\u003e\nVideo\n\u003c/div\u003e\n\u003ch1 class='rp-title' id='video-title'\u003e\nScientist develop new water filter\n\u003c/h1\u003e\n\u003cdiv class='rp-actions'\u003e\n\u003cdiv class='mr-1'\u003e\n\u003ca class=\"btn btn-success\" data-posthog-event=\"Signup: LP Signup Activity\" data-posthog-location=\"body_link_boclips\" data-remote=\"true\" href=\"/subscription/new\"\u003e\u003cspan\u003e\u003cspan\u003eGet Free Access\u003c/span\u003e\u003cspan class=\"\"\u003e for 10 Days\u003c/span\u003e\u003cspan\u003e!\u003c/span\u003e\u003c/span\u003e\u003c/a\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class='rp-body'\u003e\n\u003cdiv class='rp-info'\u003e\n\u003cdiv aria-label='Hide resource details' class='rp-hide-info' role='button' tabindex='0'\u003e\u0026times;\u003c/div\u003e\n\u003ci aria-label='Expand resource details' class='rp-expand-info fai fa-solid fa-up-right-and-down-left-from-center' role='button' tabindex='0'\u003e\u003c/i\u003e\n\u003ci aria-label='Compress resource details' class='rp-compress-info fai fa-solid fa-down-left-and-up-right-to-center' role='button' tabindex='0'\u003e\u003c/i\u003e\n\u003cdiv class='rp-rating'\u003e\n\u003cspan class='resource-pool'\u003e\n\u003cspan class='pool-label'\u003ePublisher:\u003c/span\u003e\n\u003cspan class='pool-name'\u003e\n\u003cspan class='text'\u003e\u003ca data-publisher-id=\"30356011\" href=\"/search?publisher_ids%5B%5D=30356011\"\u003eCurated Video\u003c/a\u003e\u003c/span\u003e\n\u003c/span\u003e\n\u003c/span\u003e\n\u003c/div\u003e\n\u003cdiv class='rp-description'\u003e\n\u003cspan class='short-description'\u003eAP TelevisionStanford, California, recent1. Close shot bottle of carbon nanotubes2. Various David Schoen preparing water filter demonstration3. SOUNDBITE (English) David Schoen, Postdoctoral Researcher in Materials Sciences, Stanford...\u003c/span\u003e\n\u003cspan class='full-description hide'\u003eAP Television\u003cbr/\u003eStanford, California, recent\u003cbr/\u003e1. Close shot bottle of carbon nanotubes\u003cbr/\u003e2. Various David Schoen preparing water filter demonstration\u003cbr/\u003e3. SOUNDBITE (English) David Schoen, Postdoctoral Researcher in Materials Sciences, Stanford University:\u003cbr/\u003e\"We've been developing a technology that allows us to use a couple of simple inks in order to turn cotton into a high throughput bacteria filtering device.\"\u003cbr/\u003e4. Medium shot Schoen soaking cotton in carbon nanotube ink\u003cbr/\u003e5. Extreme close shot soaked cotton\u003cbr/\u003e6. Close shot Schoen\u003cbr/\u003e7. Close shot cotton in beaker\u003cbr/\u003e8. SOUNDBITE (English) David Schoen, Postdoctoral Researcher in Materials Sciences, Stanford University:\u003cbr/\u003e\"Other people in my lab had been trying to make cotton conductive for a variety of other purposes, for instance batteries and that kind of work. And so we had this idea a couple years ago that if we could somehow combine silver nanowires, which are fundamentally antibacterial in an intimate way with water, mix it at a very small scale, and then apply a voltage to the entire thing, we might be able to kill bacteria at an enhanced rate. The idea is very simple, we almost wanted to make a nanoscale bug zapper that would just be killing ecoli.\u003cbr/\u003e9. Close shot silver nanotubes\u003cbr/\u003e10. Schoen drips nanowires onto cottton with carbon on it already\u003cbr/\u003e11. Three types of filters - he opens dish with cotton coated only in silver\u003cbr/\u003e12. Filters with only silver nanowires \u003cbr/\u003e13. Zoom in filter with bacteria cultured on it, shows that bacteria avoids areas with silver\u003cbr/\u003e14. Various Stanford campus\u003cbr/\u003e15. Various signs for McCullough Building, Department of Materials Sciences\u003cbr/\u003e16. Yi Cui arriving on bicycle\u003cbr/\u003e17. Set up Yi Ciu\u003cbr/\u003e18. SOUNDBITE (English) Yi Cui, Associate Professor of Materials Science and Engineering, Stanford University:\u003cbr/\u003e\"It's very easy to use nanotubes to make the cotton conducting, the textile conducting, so we used nanotubes. And then silver came along because we wanted to use silver for another function. Silver intrinsically is antibacterial. So if you put silver nanowires into the filter, you don't need to do anything, and the bacteria cannot grow onto these filters. So eventually we have two functions. To make the filter conducting, and to make the filter antibacterial without even applying voltage.\"\u003cbr/\u003e19. Yi Cui drawing cotton fibre covered with carbon nanotubes on white board\u003cbr/\u003e20. Close shot Yi Cui drawing silver nanowires\u003cbr/\u003e21. SOUNDBITE (English) Yi Cui, Associate Professor of Materials Science and Engineering, Stanford University:\u003cbr/\u003e\"When we talk about low cost right here, of these filters, and it can certainly reach a potential low cost for the developing countries. I think the biggest savings come later - it's the amount of energy we use for water filtration, use our filters, it's much smaller than the existing filters, that's where you save a lot of money.\"\u003cbr/\u003e22. Close shot alligator clip with wire attached\u003cbr/\u003e23. Schoen connects wire to funnel where water will be poured\u003cbr/\u003e24. Schoen pours water into filter\u003cbr/\u003e25. Close shot water in funnel\u003cbr/\u003e26. Close shot funnel\u003cbr/\u003e27. Close shot water dripping\u003cbr/\u003e28. Extreme close shot water dripping\u003cbr/\u003eA team of researchers at Stanford University have found a way to purify water that they think will be faster and cheaper than existing methods.\u003cbr/\u003eThey're now looking at ways of turning the so called \"nano-scale bug zapper\" into a product that could be sold on a mass scale.  \u003cbr/\u003eResearchers at Stanford University's department of Materials Science and Engineering created the filter by coating cotton with tiny particles called nanomaterials and running a current through the cloth which kills bacteria as water runs through it.\u003cbr/\u003eHere researcher David Schoen demonstrates how the filter is made. He fills the bottom of a test tube with carbon nanotubes mixed with water and a bit of detergent and dips a cotton square into the liquid.\u003cbr/\u003eSmall cotton panels are being used, but the filter could also be made using layers of coated cotton cloth.\u003cbr/\u003eLater, Schoen drips a mixture of silver nanotubes and methanol onto the carbon-coated cotton.\u003cbr/\u003eMost water filters use a method called size-exclusion, meaning they trap bacteria in the filter as the water passes through. This filter has much larger pores so that bacteria are not trapped, but are instead killed as they move through the mesh.\u003cbr/\u003eThe cotton is made into a conductor when the carbon nanotubes coat its surface and silver nanowires attach on one side and stretch out into the spaces between the cotton fibres. Both types of particles are on the order of billionths of a metre thick. The high conductivity created by this method means that less voltage is required to electrify it.\u003cbr/\u003e\"Other people in my lab had been trying to make cotton conductive for a variety of other purposes, for instance batteries and that kind of work. And so we had this idea a couple years ago that if we could somehow combine silver nanowires, which are fundamentally antibacterial in an intimate way with water, mix it at a very small scale, and then apply a voltage to the entire thing, we might be able to kill bacteria at an enhanced rate. The idea is very simple, we almost wanted to make a nanoscale bug zapper that would just be killing ecoli,\" says Schoen. \u003cbr/\u003eStill in very early stages, the technology killed more than 98 percent of Escherichia Coli bacteria in a lab test using 20 volts of electricity, but it must be able to kill 100 percent to effectively purify drinking water.\u003cbr/\u003eOn filters that have been cultured for bacteria, the bacteria avoids the areas covered in silver.\u003cbr/\u003eSchoen is a member of Associate Professor Yi Cui's lab, which has recently been making experimental batteries from paper and cloth coated in nanomaterials. \u003cbr/\u003eStarting from their battery work, the researchers thought of the idea to use cotton coated in a conducting metal to kill bacteria. A neighbouring lab provided the idea of using silver as an antibacterial agent, and the team decided to try combining the two.\u003cbr/\u003eIn addition to the inexpensive materials needed to make it, Cui says the biggest savings will come from the low energy required to operate the filter.\u003cbr/\u003e\"When we talk about low cost right here, of these filters, and it can certainly reach a potential low cost for the developing countries. I think the biggest savings come later - it's the amount of energy we use for water filtration, use our filters, it's much smaller than the existing filters, that's where you save a lot of money.\"\u003cbr/\u003eTo apply current to the demonstration, Schoen attaches one alligator clip to the cotton, and arranges a panel of copper mesh and hold the other clip.\u003cbr/\u003eThen it's time to pour water through the filter. Most filters require strong pressure to push water through very small pores, but in this case gravity does the job. At one metre squared the filter would be running at about 80,000 L per hour, Schoen says.\u003cbr/\u003eThat's one reason why this filter would require only about one-fifth that of a traditional filter. The new method consumes about 200 joules of energy per litre, about the amount of energy used by a 100-watt light bulb in two seconds. A typical filtration system that removes bacteria uses about 1000 joules of energy per litre and would run at a slower rate for a filter of the same size according to Schoen.\u003cbr/\u003eThat's very good news for people who need clean water in the far reaches of the globe as Yi Cui, Associate Professor of Materials Science and Engineering, Stanford University explains. \u003cbr/\u003e\"When we talk about low cost right here, of these filters, and it can certainly reach a potential low cost for the developing countries. I think the biggest savings come later - it's the amount of energy we use for water filtration, use our filters, it's much smaller than the existing filters, that's where you save a lot of money.\"\u003cbr/\u003eNow the team is considering ways to make the filter into a product that could be manufactured for sale in the future.\u003cbr/\u003e\u003c/span\u003e\n\u003c/div\u003e\n\u003cdiv class='action-container flex justify-between'\u003e\n\u003cbutton aria-expanded='false' aria-label='Read more description' class='rp-full-description' type='button'\u003e\n\u003ci class='fai fa-solid fa-align-left'\u003e\u003c/i\u003e\n\u003cspan id='read_more'\u003eRead More\u003c/span\u003e\n\u003c/button\u003e\n\u003cdiv class='rp-report'\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv aria-labelledby='resource-details-heading' class='rp-info-section'\u003e\n\u003ch2 class='title' id='resource-details-heading'\u003eResource Details\u003c/h2\u003e\n\u003cdiv class='rp-resource-details 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