Water Pollution Prevention and Treatment using Nanotechnology

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If nanotechnology is to represent societal as well as technical progress, It will have to contribute to the solution of global problems such as water quality. Providing clean and affordable water to meet human needs is a grand challenge of the 21st century. Worldwide, water supply struggles to keep up with the fast growing demand, which is exacerbated by population growth, global climate change, and water quality deterioration. The need for technological innovation to enable integrated water management cannot be overstated. Nanotechnology holds great potential in advancing water and wastewater treatment to improve treatment efficiency as well as to augment water supply through safe use of unconventional water sources.

Given the importance of clean water to people in developed and developing countries, numerous organizations are considering the potential application of nanoscience to solve technical challenges associated with the removal of water contaminants. Technology developers and others claim that these technologies offer more effective, efficient, durable, and affordable approaches to removing specific types of pollutants from water. A range of water treatment
devices that incorporate nanotechnology are already on the market and others are in advanced stages of development. These nanotechnology applications include:

• Nanofiltration membranes, including desalination technologies;
• Attapulgite clay, zeolite, and polymer filters;
• Nanocatalysts;
• Magnetic nanoparticles; and
• Nanosensors for the detection of contaminants

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Water Pollution Prevention and Treatment using Nanotechnology

  1. 1. WATER POLLUTION PREVENTION AND TREATMENT USING NANOTECHNOLOGY By: Name : Kavaiya Ashish Rajeshkumar Roll No:U10CH010 Guide : Dr.Z.V.P. Murthy Chemical Engineering Department, Sardar Vallabhbhai National Institute of Technology, Surat-395007
  2. 2. Introduction : Today Availabilty of claen,abundant fresh water for human use is among the most pressing issues in the world. More than One Billion people In the World lack access to clean water, and things are getting worse. Nanotechnology encompasses a broad range of tools, techniques, and applications and is widely perceived as one of the most significant technologies of the 21st century. Nanomaterials are manufactured materials with a structure between approximately 1 nanometer (nm) and 100 nm.Their unique physicochemical (e.g., size, shape) and surface (e.g., reactivity, conductivity) properties contribute to the development of materials with novel properties and technical solutions to problems that have been challenging to solve with conventional technologies. 2
  3. 3. Water purification using nanotechnology exploits nanoscopic materials Fullerenes NanoParticles Composed entirely of Carbon. Metallic, ceramic or inorganic. Tube shaped Dimensions 1-100nm. Bucky balls. Large surface area, very reactive. Nanotubes. Exhibit interesting mechanical, magnetic, optical, chemical properties. 3 Carbon nanotubes. Borosilicate glass nanoparticles.
  4. 4. Pollution Prevention by Nanotechnology A reduction in the use of  Raw materials,  Water  other resources The elimination or reduction of waste and on the other hand to more efficient use of energy or involvement in energy production. The implementation of green chemistry principles for the production of nanoparticles and for nanotechnological applications in standard chemical engineering will lead to a great reduction in waste generation, less hazardous chemical syntheses, improved catalysis and finally an inherently safer chemistry. 4
  5. 5. Water Treatment 1. Nanofiltration 2. Catalytic Degradation of Water Pollutants. 3. Adsorption of Pollutants 4. Magnetic Nanoparticles 5. Nanosensors 5
  6. 6. 1.Nanofiltration: NF membranes are pressure-driven membranes with properties between those of reverse osmosis and ultrafiltration membranes and have pore sizes between 0.2 and 4 nm. Nanof iltration membranes (NFmembranes) are used in water treatment for drinking water production or wastewater treatment  NF membranes have been shown to remove turbidity, microorganisms and inorganic ions such as Ca and Na. They are used for softening of groundwater (reduction in water hardness), for removal of dissolved organic matter and trace pollutants from surface water, for wastewater treatment (removal of organic and inorganic pollutants and organic carbon) and for pretreatment in seawater desalination. 6
  7. 7. Seawater Desalination using Nanofiltration Method – The Long Beach Method Seawater filtered to remove suspended solids. Stage 1: Filtered seawater pumped under high pressure through nanofiltration membrane. Only smallest 12% of salt molecules pass through Stage 2: Water from Stage 1 is pumped under lower pressure through second nanofiltration Membrane. Blocks passage of almost all remaining salts. High quality potable water produced. Energy savings: Traditional desalination method pressure required for pumping: 1000pounds per square inch(psi). Long Beach Method: 525psi first stage, 250psi second stage. Energy savings: 20-30% 7 Pilot plant running from 2001.
  8. 8. 2. Catalytic Degradation of Water Pollutants Nanoparticles serve as catalysts. Chemically degrade pollutants. Nano titanium-dioxide particles for degrading organic as well inorganic pollutants. In water, photo-oxidation occurs primarily through hydroxyl radicals. Because TiO2 requires ultraviolet light for excitation, it has been sensitized to visible light by dyes, through incorporation of transition metal ions or by doping with nitrogen . Nanoscale zerovalent Fe0 & bimetallic Fe0 detoxify organic & inorganic pollutants in aqueous solutions. Nanoscale zerovalent iron (nZVI) can reduce not only organic contaminants but also the inorganic anions nitrate, which is reduced to ammonia, perchlorate (plus chlorate or chlorite), which is reduced to chloride, selenate, arsenate, arsenite and chromate . 8
  9. 9. Soil and Groundwater Remediation by nZVI Granular ZVI in the form of reactive barriers has been used for many years at numerous sites all over the world for the remediation of organic and inorganic contaminants in groundwater . 9
  10. 10. With nZVI, two possible techniques are used: 1. Immobile nZVI is injected to form a zone of iron particles adsorbed on the aquifer solids 10
  11. 11. 2. Mobile nZVI is injected to form a plume of reactive Fe particles that destroy any organic contaminants that dissolve from a DNAPL (dense nonaqueous phase liquid)source in the. 11
  12. 12. 4. Magnetic Nanoparticles Magnetic nanoparticles offer advantages over non-magnetic nanoparticles because they can easily be separated from water using a magnetic field.  Separation using magnetic gradients, the so-called high magnetic gradient separation (HGMS), is a process widely used in medicine and ore processing. This technique allows one to design processes where the particles not only remove compounds from water but also can easily be removed again and then be recycled or regenerated. This approach has been proposed with magnetite (Fe3O4), maghemite (gFe2O3) and jacobsite (MnFe2O4) nanoparticles for removal of chromium (VI) from wastewater. Water-soluble CNTs have been functionalized with magnetic iron nanoparticles for removal of aromatic compounds from water and easy separation from water for re-use. 12
  13. 13. 3. Adsorption of Pollutants Sorbents are widely used in water treatment and purification to remove organic and inorganic contaminants. Eg.activated carbon and ion-exchange resins . The unique structure and electronic properties of some nanoparticles can make them especially powerful adsorbents The removal of metals and other inorganic ions, mainly nanosized metal oxides but also natural nanosized clays have been investigated Chemically modified nanomaterials have also attracted a lot of attention, especially nanoporous materials dues to their exceptionally high surface area. 13
  14. 14. 5. Nanosensors Nanosensors are any biological, chemical, or surgical sensory points used to convey information about nanoparticles to the macroscopic world. Nanosensors for the detection of contaminants and pathogens can improve health, maintain a safe food and water supply, and allow for the use of otherwise unusable water sources. New sensor technology combined with micro- and nanofabrication technology is expected to lead to small, portable, and highly accurate sensors to detect chemical and biochemical parameters. BioFinger is developing a handheld device that incorporates nano- and microcantilevers on a microchip. The system could be used to analyze chemicals and bacteria in water. 14
  15. 15. Product How it works Importance Developers Nanorust to remove Magnetic India, Bangladesh Rice University, arscenic nanoparticles of iron and other developing United States. oxide suspended in countries suffer water bind arscenic, thousands of cases of which is then arscenic poisoning removed with a each year, linked to magnet poisoning of wells. Desalination A combination of Already in the University of membrane polymers and market, this California, Los nanoparticles that membrane enables Angeles and draws in water ions desalination with NanoH2O and repels dissolved lower energy costs 15 salts. than reverse osmosis.
  16. 16. Product How it works Importance Developers Nanofiltration Membrane made up of Field tested to treat Sachen Industries, Membrane polymers with a pore drinking water in China Korea. size ranging from 0.1- and desalinate water in 10nm Iran. Using this membrane requires less enrgy than reverse osmosis. Nanomesh waterstick A straw like filtration The waterstick cleans the device that uses carbon water as it is drunk. nanotubes plaed on a a prototype and the final material. , United States. Doctors in Africa are using flexible, porous Seldon Laboratories product is said to be available at an affordable cost in developing countries. 16
  17. 17. Product How it works Importance Developers World Filter Filter using a Designed specifically for KX Industries, US nanofibre layer, made the household or up of polymers, community level use in resins, ceramics and developing countries. The other materials that filters are effective, easy to remove contaminants. use and require no maintenance. Pesticide Filter Filter using Pesticides are often found in Indian Institute of nanosilver to adsorb the developing countries and then degrade water supply. This pesticide Chennai, India and three pesticides filter can provide a typical commonly found in Indian household with 6000 Limited, India. the Indian water liters of clean water in one supplies. year. Technology, Eureka Forbes 17
  18. 18. Nanotechnology to water treatment devices appears to be driven by several factors including, but not limited to, Reduced costs, Improved ability to selectively Remove contaminants, Durability, and size of device. Proper studies are to be carried out to assess any harmful effects on environment and living beings. 18
  19. 19. And Last… 19
  20. 20. References : [1] P. Gleick, The World's Water—The Biennial Report on Freshwater Resources , Pacifi c Institute, Oakland, California, 1998, p. 40. [2] B. Nowack, “Pollution Prevention and Treatment Using Nanotechnology,” Environmental Aspects, ISBN: 978-3-527-31735-6, Date 15 JUL 2010 [3]T.Hillie, M.Munasinghe, M.Hlope, Y. Deraniyagala, “Nanotechnology,Water & Development,” http://www.merid.org/~/media/Files/Projects/nanowaterworkshop/NanoWaterPaperFinal.ashx ,July 2010 [4] S. C. Chang, P. Adriaens , “Nano-Immunodetection and Quantification of Mycobacteria in Metalworking Fluids,” Eng. Sci. 2007, 24, 58. [5] N. Savage, M. Diallo, J. Duncan, A. Street, R. Sutich, Nanotechnology Applications for Clean Water, New York: William Andrew Inc.2009 20

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