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Electrified nanofilter An upsrisng filtration technique

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    Electrified nanofilter  An upsrisng filtration technique Electrified nanofilter An upsrisng filtration technique Document Transcript

    • ELECTRIFIED NANO FILTER AN UPRISING FILTRATION TECHNIQUE USING NANOTEHNOLOGY N.V.N.S.Srikar1 1. B.Tech Third year ECE, Pragati Engineering College. Ph No: 9505454446 Registration ID: 0126130958 G.S.Charan teja2 2. B.Tech Third year ECE, Pragati Engineering College. Ph No: 9640943863 Registration ID: 0126131135 T.Satish Kumar3 3. B.Tech Third year ECE, Pragati Engineering College. Ph No: 9533374228 Registration ID: 0126143122 Abstract--- Contrary to the past, our recent developed technological society has made miracles to our life. In response to the rapidly changing face of technology and demand for physically smaller with greater efficiency in every requirement .This presentation is about a technology which is continuously revolutionizing, making exciding breakthroughs in every field. This technology was coined as Nanotechnology, one of the leapfrogging technologies on the crossroads of the 21st century. Our natural heritage rivers, seas and oceans has been exploited, mistreated and contaminated and which is becoming predominant issue in India in these recent years and leading to death of over one lakh people annually and making around 70 million suffering with many waterborne diseases. In this paper we will mainly accentuate you about the construction of an“ELECTRIFIEDNANO FILTER” from exploiting nanotechnology so that how it can be employed as a water purification system. Keywords: revolutionizing, exploited, accentuate Nanotechnology, purification 1) INTRODUCTION: 1.1) what is nano technology? : Nanotechnology is the manipulation of matter on atomic and molecular scale. It deals with developing materials, devices, or other structures possessing at least one dimension sized from 1 to 100 nanometers. A nanometer is one-billionth of a meter, smaller than the wavelength of visible light or about one ten-thousandth of the thickness of a human hair. The concepts that seeded nanotechnology were first discussed in 1959 by renowned physicist Richard Feynman in his talk “There's Plenty of Room at the Bottom” Later with the discovery of fullerenes in 1985 by Kroto, Heath, O’Brien, Curl, and Smalley and the facile synthesis developed by Kraetschmer a new class of molecules has been discovered that build up closed cages. The most well-known representative of this new allotrope is the C60- molecule which is nanometer in diameter with a remarkable discovery that has puzzled and amplified the advancement in the nanotechnology research. 1.2) Water – borne diseases in India: With two thirds of the earth surface covered by water and the human body consisting of 75 percent of it, it is evidently clear that water is one of the prime elements responsible for life on earth. Water covers 71% of earth surface of which only 0.3% is fresh water When it comes to water and sanitation in India our natural heritage (rivers, seas and oceans) has been exploited, mistreated and contaminated due to this out of 1.42 million villages in India, 1,96,813 are effected by contamination of water, 72% of rural India has no improved sanitation facilities and ground water in one –third of India’s 647 districts is not fit for drinking due concentration of chemicals exceeds the tolerance levels and in turn becoming victims to the water
    • borne diseases, which account for about 80% of sickness in India and leading to death of over one lakh people annually and making 70 million sufferers to these diseases. A world resources report sated that about 70% percent of India’s water supply, is seriously polluted with sewage effluents. According to UN report: India’s water quality is poor- it ranks 120th among 122 nations in terms of quality of water available to its citizens. 2) NANO FILTERS: The purpose of a water filter is to screen out harmful stuff and mechanical filtration is currently the most common method of cleansing water. Filters use a mechanical process meaning the particles are trapped in a very fine porous element and prevented from coming out the clean water end. The general criteria for a filter are: 1) Pore Size, 2) Pump Force, 3)Cost 4) Serviceability. The Nanofiltration (NF) is a cross-flow filtration technology which ranges somewhere between ultra filtration (UF) and reverse osmosis (RO). The nominal pore size of the membrane is typically about 1 nanometer. In much of the developing world, clean drinking water is hard to come by, and nanotechnology provides one solution. While Nano filtration is used for the removal of contaminants from a water source, it can also commonly used for desalination. The recent development in nanofiltration process is the usage of electricity with nanofiltration can completely wipe out the chemicals and viruses, bacteria etc in water. 2.1) Principle of Electrified Nano filter: The electrified Nano filter is a textile based multiscale device which use the principle of electrical sterilization of water using silver Nano wires, carbon Nano tubes &cotton. The key is coating the filter fabric – ordinary cotton-with nanotubes and silver nanowires, and then electrifying it. This approach, which combines several materials spanning three very different Fig 1: Principle of filtration length scales with simple dying based fabrication, makes a gravity fed device operating at 100000L/h- m2.It’s inexpensive ,is very resistant to clogging, and uses much less electricity than systems that require the water to be pumped through them. 2.2) SYNTHESIS OF CARBON NANOTUBES: Nanotube is the member of the fullerene structural family. Their name is derived from their long, hollow structure with the walls formed by one-atom-thick sheets of carbon, called graphene Carbon nanotubes (CNT’s) have been under scientific investigation for more than fifteen years because of their unique properties that predestine them for many potential applications. Fig 2: image of nanotubes Carbon nanotube properties depend on how you roll the sheet. Because of sp2 bonds are composed entirely these bonds are stronger than the sp3 in diamond, provide nanotubes with unique strength .There are three unique geometries of carbon nanotubes also referred to as flavors. The three flavors are armchair, zigzag, and chiral with right arrangement of carbon atoms, carbon nanotubes are hundred times stronger than steel but 6 times lighter in weight. a) ARC DISCHARGE METHOD : Arc discharge method is the most common and easiest way to produce CNT’s, creates CNT’s through arc-vaporization of two carbon rods placed end to end, A chamber containing a graphite cathode and anode contains evaporated carbon molecules in a buffer gas such as helium& also contains some amount of metal catalyst particles such as cobalt, nickel,. DC current of 50 to 100A is driven by a potential difference of approximately 20 V passed through the chamber while the chamber is also pressurized and heated to ~4000K. about half of the evaporated carbon solidifies on the cathode tip into a "cylindrical hard deposit." The remaining carbon condenses into "chamber soot" around the walls of the chamber and "cathode soot" on the cathode. It yields either single-walled or multi-walled carbon nanotubes The advantage of this method is
    • that it produces a large quantity. But the main disadvantage is that there is relatively little control over the alignment of the produced nanotubes, which is critical to their characterization and role. Furthermore, due to the metallic catalyst included in the reaction, and requires further purification - to separate the CNT’s from the soot Methods such as oxidation, centrifugation, filtration, and acid treatment have been used. Fig 3:mechanishm of arc discharge b) LASER ABLATION: Laser ablation is the process of removing material from a solid (or occasionally liquid) surface by irradiating it with a laser beam. At low laser flux, the material is heated by the absorbed laser energy and evaporates or sublimates A quartz tube containing a block of graphite is heated in a furnace. A flow of argon gas is maintained throughout the reaction. A laser is used to vaporize the graphite within the quartz. The carbon vaporizes, is carried away by the argon, and condenses downstream on the cooler walls of the quartz. Nanotubes develop on the cooler surfaces of the reactor as the vaporized carbon condenses. The laser ablation method yields around 70% and produces primarily single-walled carbon nanotubes (SWNT’S). Fig 4: mechanism in laser ablation c) CHEMICAL VAPOR DEPOSITION (CVD): Chemical vapor deposition is a chemical process used to produce high-purity, high- performance solid materials. The CVD method extends this idea by embedding these metallic particles (iron, in the case of the seminal paper) in properly aligned holes in a substrate (silicon, in this case). a substrate is prepared with a layer of metal catalyst articles, most commonly nickel, cobalt, iron, or a combination. Essentially, tubes are drilled into silicon and implanted with iron nano particles at the bottom. Then, a hydrocarbon such as acetylene is heated and decomposed onto the substrate. The carbon comes into contact with the metal particles embedded in the holes and starts to form nanotubes that are "templated" from the shape of the tunnel. It turns out that the carbon nanotubes grow very long and very well aligned, in the angle of the tunnel. Fig 5: mechanism in CVD 2.3) SYNTHESIS OF SILVER NANOWIRES: a) Physical vapor deposition (PVD) : It describes a variety of vacuum deposition methods used to deposit thin films by the condensation of a vaporized form of the desired film material onto various work piece surfaces The coating method involves purely physical processes such as high-temperature
    • vacuum evaporation with subsequent condensation b) Laser ablation: It is the process of removing material from a solid (or occasionally liquid) surface by irradiating it with a laser beam. At low laser flux, the material is heated by the absorbed laser energy and evaporates or sublimates Chemical Approach: The most common approach for synthesis of silver nanoparticles is chemical reduction by organic and inorganic reducing agents. In general, different reducing agents such as sodium borohydride, elemental hydrogen, polyol process, Tollens reagent and the tri sodium citrate reduction. A large excess of sodium borohydride is needed both to reduce the ionic silver and to stabilize the formed nanoparticles. The silver nitrate reduction reaction can be written as AgNO3 + Na BH4  Ag +0.5 H2 +0.5 B2H6 + N aNO3 Fig 2.Electron microscope image of silver nanowires 3) MAKING AND PROCESS OF FILTRATION: The research was initially started with basic criteria of designing and introducing a filter that could provide an affordable, clean and low cost drinking water Initially they started with basic cotton as their key source of filter as it is a material which is very economical in terms of cost, durable & widely available Silver has long been known to cultures all around the world for many centuries to have anti microbial& bacterial properties to kill bacteria. And at nanometer scale the anti bacterial property of the silver has enhanced & it possesses the highest electrical conductivity of any element And recent research found that carbon nano tubes were good conductors of electricity .so the researchers reasoned the two materials in concert would be effective against bacteria and other viruses and chemicals. So they treated the cotton with silver nanoparticles and added a layer of carbon nanotubes to increase the filter’s electricalconductivity. With a continuous structure along the length, you can move the electrons very efficiently and really make the filter very conducting .with a serious of experiments with the final coated filter by running with various strengths of electrical current they finally operated at 20 volts which gave them the required results. . The big advantage of the nanomaterials is that their small size makes it easier for them to stick to the cotton. The nanowires range from 40 to 100 billionths of a meter in diameter and up to 10 millionths of a meter in length. The nanotubes were only a few millionths of a meter long and as narrow as a single billionth of a meter. Because the nanomaterials stick so well, the nanotubes create a smooth, continuous surface on the cotton fibers. The longer nanowires generally have one end attached with the nanotubes and the other end branching off, poking into the void space between the cotton fibers.
    • Fig.3.process of filtration Process in general filters that physically trap bacteria and allow the clean water .but this filter instead of physically trapping bacteria; it lets them flow on through the water. But by the pathogens have passed through, the device kills them as an electrical field of 20v runs through the highly conductive “Nano coated” cotton. 4) COMPARISON WITH OTHER FILTRATION PROCESS: This table gives the information about the nanofiltration with other filtration techniques: (-) = not effective, (+) = low effectiveness,(++) = moderate effectiveness, (+++) = high effectiveness, (++++) = very high effectiveness 4.2) ADVANTAGES: • Purifies water at low cost. • Process of filtration is 80,000 times faster than existing filters. • Uses less voltage to kill bacteria and viruses. • Can be easily used even in remote areas. • Water flows through filter is quickly & easily due to large pores • No clogging problem. • No bio fouling • Low electricity requirement. 4.3) DISADVANTAGES: • Cannot wipeout some of the chemicals. • A single filter can only kill 98% of the bacteria. • Traces of silver particles & CNT residue 5) CONCULSION: By adapting to this electrified nano filtration process we can improve the prevailing situation faced in the purification of water as it can be used from macro (national & state) level to the micro (district & village) level 6)BIBLIOGRAPHY: Different filtration process protozoa Bacteria viruses chemicals Micro filtration ++++ ++ - - Ultra filtration ++++ ++++ ++ + Nano filtration ++++ ++++ ++++ ++ Reverse osmosis ++++ ++++ ++++ +++ Distillation systems ++++ ++++ ++++ ++ Uv filtration systems ++++ ++++ +++ -
    • 1. http://news.stanford.edu/news/2010/august/n ano-pure-water-083110.html 2. http://pubs.acs.org/doi/abs/10.1021/nl10194 4e?journalCode=nalefd 3. http://www.waterfilterdude.com/water- filter.shtml 4. http://www.deccanherald.com/content/6374 0/poor-water-quality-serious-threat.html 5. http://www.onlymyhealth.com/top-water- related-diseases-in-india-1300271205 6. http://in.reset.org/blog/water-borne-diseases- india
    • 1. http://news.stanford.edu/news/2010/august/n ano-pure-water-083110.html 2. http://pubs.acs.org/doi/abs/10.1021/nl10194 4e?journalCode=nalefd 3. http://www.waterfilterdude.com/water- filter.shtml 4. http://www.deccanherald.com/content/6374 0/poor-water-quality-serious-threat.html 5. http://www.onlymyhealth.com/top-water- related-diseases-in-india-1300271205 6. http://in.reset.org/blog/water-borne-diseases- india