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Removal of heavy metal by nano metal oxide


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mudasir malik

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Removal of heavy metal by nano metal oxide

  2. 2. Contents  Introduction  Effect of heavy metals  Removal of heavy metals by nano metal oxide  General mechanism  conlusion
  3. 3. INTRODUICTION TO HEAVY METALS  Metals with relatively high densities, atomic weights, or atomic number.  Most common heavy metal are leads (Pb), arsenic (As), cadmium (Cd), and mercury (Hg).  They are highly toxics
  4. 4. Why to remove heavy metals  High demand of water due to increase in population  High amount of waste water is generated  They are non-biodegradable and have toxic effect  They enter into the food chain  They destablize the ecosystem
  5. 5. Effect of heavy metals  Mercury can build up into the tissues of fishes and may be harmful to people and other animals that eat them.  Aluminum accumulate in the gills of fishes and cause inhalation problem.  On the accumulation of heavy metals plants experiences oxidative stretch and cellular damage.
  6. 6. Removal of heavy metals by nano metal oxide  It is adsorption technique.  Involve the mechanism of photo catalysis.  Reduction by nano particles.  Different metal oxides are used.
  7. 7. General mechanism  Absorb the UV radiation from the sun and produced the hole and electron pair  Electron of VB become excited when illuminated by light.  Excess energy of this electron promoted them to conduction band.  Creation of negative electron and positive hole.
  8. 8.  Photo catalytic mechanism is initiated by absorption of photon (hv) producing electrons and holes on the surface of nanoparticle  Excited state electron and hole can- 1. Recombine and dissipate heat 2. React with electron donor and electron accepter
  9. 9. Photocatalysis
  10. 10. Photo catalysis by ZnO
  11. 11. Magnetic removal
  12. 12. ADVANTAGES  Convenient approach for separating and removing contaminants by applying external magnetic fields.  High efficiency for absorption maintained even after many absorption cycle  High surface area  Low cost
  13. 13. Limitation  Corrosion of metal surface  UV light is required
  14. 14. Conclusion  Heavy metals are dangerous to health so they should be remove from water .  Nano technology is very efficient  Nano metals are effective in the removal of heavy metals by their photo catalytic action.
  15. 15. References  M.jamil,M.S.Zia,M.Qasim,Contamination of agro-acho system and human health hazards from waste water used for irrigation ,J.Chem.Soc.Pak,32(2010)  S.H .Peng,W.X.Wang ,X.D.Li,Y.F.Yen metal partitioning in river sediments measured by sequential extraction and biometic approaches,chemospheres 57 (2004)
  16. 16. THANKYOU